Tom Cherry

Technically, and you may know this, your existing inverter is a standalone. It doesn’t have any limitations and if you could install 3600 watts (OK…this is fact…..but not feasible) and maybe COULD eliminate your inverter.  The BATTERIES get charged by either the INVERTER or the SOLAR.  You have a 2000 Watt Inverter.  That is based on the circuitry to INVERT 2000 watts of power.  Inside the control board, is an Automatic Transfer Switch.  This ATS is rated at 3600 watts (30 Amp breaker X 120 VAC). So, when you are on shore power, and you have a “battery” that reads above 11.4 VAC and takes a trickle amount of charging current….maybe less than 10 amps, the “Control Board” says….OK…I see a battery.  I see 120 VAC on the incoming.  OK….ATS ….stay in the NORMAL CLOSED mode….let through a full 30 amps of power to the Line 1 and Line 2 circuits.  One is Microwave and the other is all internal outlets.  BUT….when there is NO 120 VAC, the ATS “swaps” and then the ATS on the Control board starts to Inverter….but it only can do 2000 Watts.  I don’t think anyone, could be wrong, has ever installed more than say 1500 watts of solar….not enough room and if you wallpapered the top, without an access walkway, then, you would need a “cherry picker” to ever remove an HVAC unit.
NOW….search is your friend.  Use WIRING in the search box.  Click on Everywhere.  Choose FILES.  There are drawings for your rig.  The  Camelot and Scepter were all the SAME.  2003 was a funky year….I’d pull the 2004 Camelot.  IF you have a main panel and a Sub Panel (120 vac Breakers in both), you have a “Winsdsor” wired MH but not a Windsor body….I can’t find a 2003 manual online.  If you have NO Subpanel and there is a single GFCI somewhere….probably lavatory, you have the equivalent of a 2006 Windsor, Camelot, Scepter.  The Dual In Dual out vs Single In Dual out is the real or only main AC distribution difference.
Bottom line, you can add whatever solar you want.  The batteries get charged by the Inverter Charger and/or Solar.  Then the Inverter delivers power based on the amp hour capacity or if being recharged via auxiliary solar, the sustained capacity.  The limiting factor is that 4 batteries, like you have, can typically deliver 2000 watts which is a function of the Inverter's circuits .  Adding MORE solar, almost, I thought, a physical impossibility, does not increase the output….only sustains it.
NOW…if you really want to be as “SOLAR” as possible…..then Lithiums are being used.  Lithiums will not fare well with your vintage charger.  We have a LOT of smart folks and use the search like this.  Solar. Or Solar Lithium in the box and then chose TOPICS.  That will give you a weeks worth of reading from the experts…
There MAY also be some info in the files….so repeat, but select FILES.
I kept this very elementary as we never know a poster or member’s level of electrical understanding.  The “why do I have no power” when plugged into shore and all breakers are on….and there ain’t no outlet breakers” is the number one quandary for most folks that have never owned a Class A RV….so, please do NOT interpret my “education” as a put down.  Many will read it and some, as they have, and  PM’d me, say WOW.  THANKS….NOW I understand….

Thanks 
The 2004 Windsor was the “last” i think of the “real Windsors” and the Semi Monoque body construction.  The 05…..maybe, but one would have to dig through the ONLINE Monaco’s website’s advertising brochures and look at the “construction” details.  They sort of did a bait and switch and then the Camelot and the Scepter Scepter and Windsor were “born”….don’t hold me to the year and how the “triplets” were born.
My “rule of thumb”.  04 did have a Dual In Dual Out as I helped our founder with his electric issues.  OF THAT I KNOW….
Then the triplets had the newer version.  A Single In Single OUT or 2 circuits.  That’ why yours would be easy to modify. A word about my “split lug” choice as folks may be snickering.  I don’t like wire nuts in a MH, and YES, Monaco used them.  I KNOW that the NEC exempted microwaves and res refers when all the Monaco’s that had GFCI’s upstream of the refrigerators and icemakers were wired that way.  SO…. Monaco was not a stickler for code….and maybe never knew the consequences.  Once Monaco started offering res refers as options, not CARTE BLANCHE, as i have only looked at at least 80% of those prints, they STOPPED and used conventional circuits or NON GFCI Protected.
That “long and boring” dissertation was to clarify that most residential and I know, all industrial & commercial contractors…..as I supervised maintenance and also used outside contractors…..told me when I was installing home generator back feeds for friends….and they had an “abandoned dryer line” and it was  #10 aka 30 Amps…..do NOT USE WIRE NUTS.  That, personally, would “GO DOUBLE” here.
I’ve had to make a few….usually works in a standard box.  In your case, I would set a box ahead of the Inverter.  I would have a #10 in (its there), a #10 out to the inverter and a #12 out to a subpanel of whatever you need for a 20 A breaker.  That’s clean.  My MEMORY…two wraps of a kraft or “paper bag” over the split lug, a special 3 M foam tape (called out in NEC and easily checked online) then maybe 2 wraps….number eludes me.  Then you encapsulate with standard electrical tape…but you make sure you keep tension on the tape (most don’t’ and put maybe 3 there.  That meets NEC…of that I know.

Ken,
Two comments.  One is minor.  I added the Year, Model and Floorplan to your Signature
NOW....your Diplomat does NOT have enough "SLots" or breaker positions to do what you want. The following is an explanation I made from assuming, incorrectly, that there was individual breakers, NOT the "Two Pole" kind like you have....so it WILL NOT WORK...but, for you own electrical education...it explains how the MH differs from the Home.  BOTTOM LINE...even a NON CONVENTIONAL, and UNAPPROVED or DANGEROUS scenario with NON interconnected 2 pole breakers is NOT an OPTION...  SOME of the Intellitec Panels, I THINK....had MORE slots....but even if they did and you could combine TWO breakers into a single ONE....IT IS NOT RECOMMENDED.....Scroll or read...the CONCLUSION is marked...at the bottom...
Your Load panel is specially built for NON 240 VAC circuits.  It is the Intellitec EMS panel.  If you look at your HOME panel, then you will see that a 240 Breaker (Dryer, Stove, Water Pump, AC or "welder" has a double sized circuit breaker.  Most folks, and not talking down to you, don't realize that one side of their panel boxes is Line 1.  The other side is Line 2.  SO, when an electrician installs a 240 VAC appliance, that breaker has contacts for BOTH SIDES.  So, one of the power or hot leads is on the LEFT side (say line 1) and the other is on the RIGHT side or line 2.  Unless you have ever put in a home panel or rewired or modified, then most don't know this.
OK....you YOUR Intellitec EMS says Line 1 on one side and Line 2 of the other.  Thus, the logic would be...  Hey, it is done at home....so just add a circuit breaker and it hooks up to Line 1 and Line 2...  Bingo figure out how to run the four wires (probably #10 or maybe #8) from the Main to wherever we can put the outlet.  THAT "running wires in a MH is a feat beyond comprehension....it would probably end up in conduit on the wall...
BUT.....even so....you CAN NOT DO IT.  WHY....  The Main Panel is NOT like your home.  The LEFT side runs horizontally.  The RIGHT side runs Horizontally.  The MAIN is in the middle.  In you HOME panel, there is a breaker, usually at the top....or the bottom.  The Line 1 buss and Line 2 buss run vertically.  The BUSS is where the breaker is attached to get power.  So, a dual pole or oversized 240 breaker is attached to both the LEFT and RIGHT side and they are INTERCONNECTED.
There is NO BREAKER MADE or MANUFACTURED that will work in that panel.  The Busses are NOT side by side or parallel or RUN VERTICALLY.  
NOW, for the REALLY ingenious folks...  WHY NOT put in a TWO LEGGED CB and replace the Front AC and the Rear AC. You could then rewire the main panel.  Put the Rear AC and the Refrigerator on to a SINGLE wide breaker...two circuits.  Thus, have a HOLE...or slot.  Put in a 40 Amp breaker that.
THEN, pull the same stunt on the OTHER side.  Front AC and Bedroom on a SINGLE SLOT Dual Breaker...and now an open slot for a 40 Amp breaker.
Technically, it should work.  From a CODE standpoint, that is NOT permitted.  A TRUE 240 Dual (two wire) breaker is SUPPOSED to be a single unit...in that when one side trips....they BOTH TRIP.  It would be a hazard if someone tripped or opened one breaker....thinking it was to CODE...and then got zapped because there was power on the OTHER LEG.  You can put up all sorts of signs and such...but by NEC....that is NOT permitted.
SO, my advice is the same as everyone else...just from an EX OSHA Electrical Safety Instructor.   I WOULD, UNDER NO CIRCUMSTANCES, DO THIS.  The electrical circuit that would test Edison just to get the wires to the location of the Dryer would be a Herculean task....and probably UGLY and expensive.  BUT, from an electrical safety standpoint....it is DANGEROUS....and could get someone killed.
CONCLUSION
Use a Combo like most do....my DW loves hers...  OR put in a 120 VAC dryer.  PROBLEM.  OPPS...  You STILL do NOT have an OUTLET for the Dryer and the Washer.  SO, again...  split a feed....do what I suggested above....which is OK for just a 120 Amp Breaker.  You already HAVE that on your Refrigerator & W/D.  THAT would be OK...and you run a NEW 120 VAC line to the area.  Perhaps someone could steal and snake a circuit up from the Block heater.  STILL adding a circuit in the laundry is NOT like the simplicity in a HOUSE... MAY be easy if they can find a line UNDERNEATH  but otherwise...in the ceiling....gonna be a NIGHTMARE.  BUT, we HAVE had folks that were good at this so I can NOT say....it can't be done...
That's it...  Hope this makes sense.

Comment….just to sort of make sure….and also follow up on Ray’s comment.  Go back to the original print. IF the Bedroom TV outlet is defective or the circuit THROUGH it….the game is called…..NO STADIUM LIGHTS.
There HAS to be POWER in and out of J Box 7.  Bad bedroom TV….no IN.  Dumbest thing I have ever seen Monaco DO… verify power out for NON microwave circuit on Inverter terminal strip and that circuit breaker (pin) is OK.  These have failed.  Relatively easy to fix….but need to get “inside” inverter to replace. THEN go to Bedroom.  IF no incoming power….and you reset the PIN….I would open up the inverter and verify the “function” of the PIN.
NOW…easy test.  I THINK the Microwave is working.  Pull terminal strip cover.  Reverse line 1 and line 2 OUTPUT.  IF the Microwave doesn’t work….then keep messing with the PIN circuit breaker or replace.
BUT..lf you still have no pwer and bedroom TV outlet dead….circuit issue….probably Bedroom TV outlet.  Replace….if no joy….then major issue.  NO WIRE NUTS or such between inverter and J Box 7.
That’s my “troubleshooting” logic….

@jfasano88
Sort of throwing in my $0.05 (inflation adjusted....LOL) comment.  
First, I have an original copy of the "Internal" Dometic 1402 Service Manual...it was the DRAFT that a Dometic support tech gave me....way back in 2009.  They published it later, but "skinnied" it down.  EDIT I downloaded the Manual that @CAT Stephen provided the link for. I have not done a page by page comparison END OF EDIT.  I used THER ORIGINAL and it was original was very good and I have shared it.  Here is it.  @Frank McElroy, I did a search this morning.  The only hit I got on 1402 was the paper on the fire extinguisher....may have been mine....as I vaguely remember writing one.  This manual needs to be in the files. I will do a search and see if I can located the final version, but this one was really great and clear and I used it many times.
OK....back on point.
IF you have an error code and it did not clear, I do NOT think that pulling the power or disconnecting it will "resolve it".  MY RECOLLECTION...was that when the power was pulled and the Refer sat and all the "stored charges" on the PCB Control Board dissipated...like it would fresh out of the box, it will come on....and the "MODE" will be AUTOMATIC.  Thus, if the board reads or "senses" 120 VAC, then it reverts to AC as the heaters will take over.  BUT, NO AC, then it defaults to Propane.  You can change that option from the panel....but, I do NOT know if that change locks it in or when you totally power down and reset, what will happen.
Second.  ER 12 is the DEFROST HEATER FOR THE FRESH FOOD COOLING IS FAULTY. OK...The manual I got was "not the best resolution....but legible.  Photos are UGLY.  However, here is a quick "copy and paste" as to how to ADDRESS ER 12.

NOW...a WORD OF CAUTION....and this is the FLOGGING of a DECEASED EQUINE.  There are several "Defrost Heaters" as well as an Icemaker Melting coil on the Dometic.  ALL ARE TROUBLE SPOTS.  Even NEW, these "out of the box" heaters are merely toaster wires in a ceramic insulator.  Ceramic will absorb a WEE TINY amount of moisture....as they age or when new.  This moisture then compromised the "Dielectric" or INSULATING properties of the Ceramic.  SO, you can get a milliamp or maybe even a microamp leakage....and one would need a lab setup to probably measure and be a PhD in Electronics.  
BUT....what happens....is that the GFCI in your Camelot, UNLESS you have rewired and corrected Monaco's "Lack of Understanding" about False GFCI Issues....will, eventually....CAUSE YOUR GREIF.  BEEN THERE....DONE THAT.  I have a LOT of electronics practical experience...and we have many, a LOT, that are smarter than me.  BUT, I do know something about how a GFCI work...your HOME refigerator is NOT on a GFCI circuit.  Your MH Microwave is NOT on the GFCI circuit.  The NEC, when your MH was built, required for Residential or maybe said differently, "ALLOWED" a dedicated circuit for your HOME Microwave and a dedicated circuit for your HOME refrigerator.  I have seen inspectors "TURN DOWN" a new home because an overzealous electrician thought that he was doing the owner a favor and putting GFCI on BOTH.  The local inspectors typically look for this.  AND they, by the code then, would require that the GFCI Breaker(s) be removed and a conventional 15 Amp breaker installed.  
BOTTOM LINE...lets get your unit up and running and clear the error coded.  THEN Private Message me @Tom Cherry.  I will go over, as I have done for more than 50 owners, the simple an STILL SAFE method of putting the "Ice Maker" Receptacle on the PROPER, per CODE THEN, NON GFCI circuit.  All the "normal GFCI" outlets are STILL protected. It was either a cost savings or perhaps "stupidity" or maybe an overzealous engineer that drew up the circuit wrong.  SIMPLE 10 minute JOB.  No meters or such.  Skill set...  must be able to safely install or replace a home receptacle.
That's it.  Get the ER 12 resolved....then PM me and you should be good to go....
 
Combined Parts 1 & 2 Dometic DRAFT 1402 Service Manual.pdf NEW & Released Dometic-NDA1402-Service-Manual.pdf

WORD OF CAUTION.  There are, in most stores, TWO grades of Cleaners.  ELECTRICAL, which is more aggressive and volatile.  That stuff will melt a CAT 5 cable and mess up a LOT of plastics.  The lower or less aggressive is ELECTRONICS CONTACT CLEANER.  Our sage advice, from a Moderator's standpoint is to NEVER use an Electrical cleaner unless it is heavy duty like on a battery.  In sensitive electronics....use ONLY ELECTRONIC cleaners.
NOW....NOT ALL ELECTRICAL CLEANERS are the same.  In the olden days...there was  MOTOR cleaner.  It was the same as Disk Brake Cleaner and it would dissolve about anything.....and sometimes stuff you did NOT want dissolved.  So, the rule was Electrical cleaner for common contacts or such....like inside an ATS...but NOT on the PCB....
There, only use the Electronic.  I HAVE melted stuff and read and don't just grab a can.  I have TWO cans...and start off with Electronics...and if it doesn't work....try Alcohol and Q-tips and rarely, unless whatever I am working on appears to be DEAD and trying Electrical Cleaner is like the "Cure may KILL the Patient".
Just a tip....and we Moderators will jump in and post a warning and that is NOT a put down of the poster....only a clarification....

Steve,
Many folks do this.  Some of the newer Models come with the Genny being started from the Chassis.  If you do that, and MY OPINION, you will be prone to more issues.  If your Chassis is dead....then you are totally INCAPACITATED.  
The other issue....the wiring for that may NOT be as simple as you might thing.  It all depends on how the battery busses (the distribution points) from each bank are made.  Could be as SIMPLE as moving one cable.  BUT, also, the folks with the newer models and higher food chain, often report a "Phantom" Genny will NOT start. We have many members whose Dynasties and above came with Cranking Battery starting and they add a supplemental battery...NOT A SMALL JOB.
NOW, to keep it simple.  Carry a set of Jumper Cables in the MH or in your TOAD.  If you JUMP or connect the HOUSE to the Chassis, you have the ability to crank the Genny.  The ONLY CAVEAT....Turn OFF each or BOTH Disconnect switches....THEN hook up the Jumpers.  Folks and I have, often do that when we get a fluke in our charging system and run down one or the other.  That is my advice....but your MH and others may (will) feel strongly about doing the conversion.
From a PRACTICAL standpoint.  YOUR Boost Switch or the ability to combine the banks is HOUSE POWERED.  SO, if you don't have ENOUGH Juice to CRANK the GENNY....then odds are, there will NOT be enough voltage or current to "engage" the Big Boy....The Big Boy has two functions.  BIRD charging....and then to let you (read the manual) put a surface charge on the CHASSIS and then be able to CRANK the Engine.  
ALSO, be aware that your BIRD must be 100% functional....otherwise if you rewire and your Chassis runs down...you have NO WAY to start the Genny....other than the KISS of Jumpering.
SO, your call...but a simple 5 minute drill to jumper the HOUSE and CHASSIS accomplishes what you want....and also gives you the OEM benefit of being able to START the MH....If you leave the MH in storage or spend a long time camping and your CHASSIS goes DOWN....a COMMON occurrence...then you have excerbated the situation...and have to start using a CAR.  That is more dangerous to the electronics in the MH....often folks have done significant damage.
THAT is why I am an advocate of "KISS"  Turn OFF both Disconnects.  Attach the Jumper Cables.  Turn the batteries back on.  Crank the Genny or conversely....crank my ENGINE....then let the run a while for either the engine (alternator) or Genny (House) to recharge.  SHUT OFF BOTH ENGINES.  TURN OFF the battery switches.  Remove the cables....turn back on and DRIVE or go on.
 

Unless Navistar changed the plumbing design, there should not have been an accumulator tank.  The original RV55 pump was an AquaTech design.  They were used from say, circa, mid to early 2000’s.  The instructions plainly state….NO Accumulator….but folks have left them in or decided they needed one.  Mixed results.  REMCO bought out the rights to the AquaTech pump….then used AquaTech as the vendor.  Don’t know now, who makes them or if they are imported.  If you use the search box and put in Remco or water pump or AquaTech…..then click on the Everywhere and there is a drop down menu.  Select Topics.  There are many topics….and one has the “original instructions” which actually tells you how to adjust the pressure.  Later on, AquaTech decided it was a “factory” adjustment with their pressure setup.  BUT…many have tweaked it.  If it is pulsing, then I would start to check the fittings.  If there is a loose one or perhaps a hose with a pinhole leak, on the inlet side, it will suck air.  It takes a few minutes to purge, but then it should be OK.  Typically, one gets longer life than you have.  
Mine was replaced under warranty in 2010.  I ended up with a new spare….so, I installed it a few years ago…. It was still in great shape.  Make sure the filter is working and cleaned.  These are usually very troublefree.

There were some “unusual” circuits around that time.  A Workhorse model would “think” that the parking brake was on, when you hit a bump and “jiggled” the seemingly rigid switch mount of the plunger….disconcerting to say the least…hit another bump….go off.
I would try to find a Ford HD truck shop.  They have the prints.  The brake pedal circuit thinks something is WRONG.  For example, is there a fluid level switch in the master cylinder?  WH had an air over hydraulic system and if the level in the HD brake reservoir got low….it warned you….check the fluid level.  If full, is there a sensor or switch on it?  But, without the chassis print….it is a crap shoot…..
OF COURSE….if you ask Google….nicely and with the right phrasing…..
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28819357/print/true.cfm#:~:text=If the engine isn't,F-53 chassis do it.
May be your issue.  NOW….is the “buzzing” you hear NORMAL….only a Ford HD Tech can tell you….one would NOT want a motor to fail that is critical to the brakes….
Let us know…..

Myron has a LOT of experience.....and information.  All I can reiterate....we have had more...  "WHAT DID I DO" posts from doing upgrades, probing around, just pulling harnesses, etc. than I can count.  I DID find a drawing on the MH....or it will be close....
Go to the Coordinates in the left..... G/H6.  That shows the wiring.  If you blow up the drawing and start to chase each pin, it is connected.."roughly".. in my opinion, through a maze of "Connections".  Working in the RRB and such, one often has to "move" things.  
SO...based on the fact that the entire plug DIED....and there are several different relays upstream...  I'm still of the opinion that there is a harness connection that was "disturbed.  
 
So, NOW, you can follow the Relays for each function....and if the Relay's are "sending out a signal....as I think ALL of them are...then there is a common denominator....as in a multipin harness connector that got bumped...  
BUT....I have been known to be wrong before....ask my DW....I think twice before she got up...  LOL...  Until you start with the Relays....determine if there IS a good signal....then it is all over.
BTW....you never commented...and I never asked.  DO THE MH TAIL LIGHTS WORK OK?
IF SO....then the Relays are OK.  I THINK that you said that you do NOT have a GROUND in the 4 or 7 pin....and when you used a KNOWN ground....that the power or signals didn't work.  THAT IS THE KEY....a bad connection....and doing all the trouble shooting of the relays, as they also control the Tail Lights...might be the SECOND STEP....as in checking the harnesses and the plugs....
BUT....That's just my thoughts....but NOW you do have the drawing...
2006 Diplomat & Other years Overall Chassis Wiring Front to Rear....BLOW IT UP.pdf

Yes.  Eternabond makes a “remover”.  On Amazon.  Purchase that.  I had all mine done.  Maybe 2 cans.  You also need a tube of Proflex.  There may be some voids in the sealer (caulk) that need to be touched up to get a smooth or uniform surface.  You need the HEAVY ROLLER to properly press down or roll out the Eternabond tape.  This is what the techs use to get the tape fully adhered.  Make sure you watch the video on removal of the toppers and count the turns when you start to “unwind” the tensioning springs.  Always install and tighten or turn them to the original installation position….unless you are well versed in how to properly adjust and tension.
if your toppers are frayed or in bad shape, then contact @throgmartin  Chris is our expert and is affiliated, still, with his original “RV TOPPER REPLACEMENT” company, Stone Vos.  I have his “vinyl” toppers….installed in 2015.  Excellent quality and still look as good as new.
 Eternabond EBR-125 2-1/2" Wide 2Lb Steel Roller. 

 
 

Time to pull the prints in your manual and learn how the MH works.  Don't know if this is your first MH or first Monaco....there ARE DIFFERENCES. This is the "ELEMENTARY Monaco Electronics - 101" 
The 120 VAC power comes from two sources.  One is SHORE and the other is your Generator.  BTW....your Generator is a 230 VAC...so you have TWO lines (Line 1 and Line 2).  It is the SAME type of power as a 50 Amp source.  IF you read about folks with Generators, make sure that you understand that your generator is different from the lower food chains....like the 8.0/7.5KW.  Your Generator needs to be run with 50% load (say all three HP/AC) for maybe half an hour every 6 months...otherwise the brushes get dirty.  NOT necessary on the smaller.  
The ATS switches the power.  When you turn ON the Generator, the ATS ASSUMES that you do NOT have pedestal power....or it "Measures" the Generator Terminals.  THEN, if there is power (as in the Genny is on), it switches to Generator.....  It ain't that smart.  BUT your Factory Monaco ATS did come with a built in Surge Suppression system.  You can pull the model number from the ATS.  The Signatures MAY have had a higher level of protection from the Dynasty.  SO, google the PN or read the manual on your ATS and look at the specs.  MOST folks do NOT change them out.  BTW....if it EVER DOES go bad, you will lose the Aladdin AC Voltage/Current screen.  There is a proprietary dedicated data bus that has to receive a coded digital signal.  When SurgeGuard upgraded or maybe Aladdin, a replacement SurgeGuard ATS will NOT have this output....so the Aladdin is useless for AC measurement.  
The output of your ATS does to the same type of panel as your HOME....a Dual Breaker 50 Amp Panel.  NOW....we are headed to Level 202....  LOL....It gets tricky from here.
There are TWO AC Panels.  One is the MAIN panel.  It has all the AC's and block heaters and such.  There are TWO 30 Amp Breakers.  BOTH feed the Inverter.  The Inverter is a DUAL IN and DUAL OUT configuration.  The inverter gets AC from the main panel...through the TWO feeds....Line 1 and Line 2.  THEN it takes that power in.  ASSUMING it does HAVE POWER....it then feeds your "critical AC stuff".  There is a SECOND panel called a Main Panel.  It has TWO Sides...same as the Main.  These sides are SPLIT....so this is generic.  There is a diagram in the panel that tells you.  You have GFCI protection for all the outlets that are within 5 or so feet of a sink or water.  There is a DEDICATED outlet for the Microwave....NOT GFCI protected.  There is a DEDICATED Outlet for the Residential Refrigerator....NOT GFCI protected.  Don't panic, as some do.  Your HOME microwave and refrigerator (98% of US) are on Dedicated circuits and NOT GFCI.  These MAY trip, false positive, an older or a "slightly cantankerous" GFCI.  This is called a nuance trip.  People who have a freezer in a garage on GFCI are the ones that end up with all the contents SPOILED as some "blip" tripped the garage GFCI.  That is why homes are configured.  BUT, the ELECTRICAL WIZARDS today are going to require GFCI on these two circuits.  Electricians and Appliance Repair folks will have a field day and their retirement account will be greatly improved.  PARDON my humor, but my wife was a professional Tax Preparer.  The partners in her firm laughed everytime the IRS Tax Code was SIMPLIFIED....they saw a 25% increase in business.  I PREDICT...as the NEC changes, the SAME increase in business for the folks that come out and tell you..."Nothing Wrong...." Just the nature of the beast.  $200 please.
NOW....REMEMBER THIS.  Your INVERTER has a SMALL ATS inside.  In order for you to have ANY internal Outlet, Microwave or Refrigerator power....you MUST have a "fair" set of batteries.  IF the Inverter says....these batteries are crap and I can't charge them....then the ATS does NOT even allow the incoming GOOD Shore or Genny Power to go through the ATS.  There is no MAGIC WAY to fix this....actually ONE....but it is a bit extreme.  You can NOT just unplug and move....  The ONLY way would be to turn ON the Block Heater and run an extension cord to the Microwave and the Refrigerator.  All the outlets are on the hard wired GFCI....so just use a second extension cord....and you will be on limited power.  NO OFFENSE, but this "QUIRK" as many call it has driven folks crazy and results in a lot of "OMG....LOST POWER" topics.  So we Moderators often post this for general information.
As to your FIRST question.  That is called the HOUSE DISTRIBTUION AREA.  That is ALL 12 VDC.  That is the HEART of your system.  All you lights, exhaust fans, water pump, etc. are 12 VDC...so you can BOONDOCK.  There is also a critical unit....all your INTERNAL LIGHTS or anything on the "Switch pads that light up".  This is an Intellitec Multiplex (MPX) System.  It has a COMPUTER or a Programmed CPU (Central Processing Unit).  It is COMPLEX...  The ONE THING you should never do....is to TURN OFF the Battery Switch by the door as you come in.  That shuts down every INTERNAL DC Circuit.  It is called the Salesman's Switch.  DUMB..
  If you turn it on and off in order not to use the switches, you also PULL the power from the CPU.  Think about unplugging a computer from the wall instead of shutting it down properly.  Then when you return....it thinks that the world came to an end.  It has to REBOOT or RESET and there are 5 downstream electronic devices that also wake up.  You do NOT have hard wired light switches and such like at home.  All the functions on the lighted key pads are ELECTRONCIALLY controlled.  SO, if the CPU goes haywire or you loose on of the 5 or so downstream modules.....whatever is on that module...will no longer work and your have a COMPLEX MPX issue.
SO....leave it ON.  When you store, hopefully you have power....and keep your House Bank charged.  Constantly turning off the batteries results in the CPU and the Modules (MPX Components) rebooting or having to reset.  YES....that is the way you "FIX" a gremlin....and folks familiar with the MPX will often do a REBOOT or use the Salesman switch.  That is the ONLY redeeming quality, most folks say, of having it.  
That's it.  No Pop Quiz....
 
 

Woody.  Memory says you had an issue with your inverter a year or two back.  Finally got it fixed.  You can domthe following as a quick check, but here is what you need to do and then, probably call Magnum.
Turn OFF house bank.  Disconnect the jumpers between each set of 2 batteries.  Measure the voltages.  If one or more is in the 4 VDC or lower….then remove them or rposition them so they are in the same set.  Don’t know if you have 4 or 8.  Pick the best batteries, reading at least 5.7 or so.  Put them in sets so that you have then back to normal or charging.  If you have an odd number of 4 VDC….then put them together….do NOT put back in the jumpers….wasting your time and messing up the charging.  You will not be able to salvage these….shorted cells.
OK…you need an even, 2, 4, 6, or 8 GOOD (not shorted cells) batteries hook up.  Then test.
BUT, on the way home…or if you are going to drive several hours….put a jumper cable between the House and Chassis.  Then drive.  Once you are home or at a CG, repeat the above…
You need to out a piece of masking tape on each battery. A, B, C….etc.  record the voltage now.  Repeat when you do the Chassis charge…compare voltages.
Post that….then go from there.  We can’t make any decisions, or at least I can’t, until we know the condition of the batteries.  Load testing is marginal.  This plan lets us know what is going on.

No experience on Seafoam and the folks recommending are knowledgeable.  I hate to make this a "Chemistry Class", but belts and suspenders are great...
Seafoam....sounds good.
Stabil...  YES, I use it all the time. I also don't like ethanol fuels.  However, the bulk of the issues with ethanol is in the minute passages of small engines with no pressurized fuel system.  ODDS are... that the fuel system will be fine.  However, that being said....here are some ideas....plus I did some research on the engine (most likely the 8.1 Vortec) and comments from folks that had it in the HD work trucks.
SO, here is my recommendation....based on building fuel injectors and also, like a lot these folks, an old hot rodder gear head.
First...  Techron Fuel additive is one of the BEST additions for ANY fuel injected system.  All fuel injected systems are a spin off (or at least they were when I was setting up a manufacturing line) from the Bosch system.  Volvo and all the German cars were very demanding and precise about what to add as a additive.  The Techron was the first one recommended by Bosch and the service manage of my local Volvo dealership was adamant about it.  THEN, I started using it as a "cleaner" or preventative and it works wonders....as in I NEVER have had a Fuel Injection issue.  If it is good enough for my 2016 C7 Corvette...that is the best I can say....Rather than pay a Chevy dealer to do a Fuel Injection Cleaning...., I would buy the 20 OZ bottles on Amazon... 
https://www.amazon.com/Chevron-65740-CASE-Techron-Concentrate-Cleaner/dp/B0097SDUTE/ref=sr_1_2_pp?crid=EIXYRQ1FU6F0&keywords=techron&qid=1694968208&sprefix=techron%2Caps%2C99&sr=8-2&th=1
Whatever the label says...and I think it is 20 oz for a 20 gallon tank, double or at least 1.5 times....so 30 OZ for 20 gallons of fuel.  Dump it in....drive it to a fuel location...and put in PREMIUM fuel.  Mobil and Shell are my top picks.  If you live near a Costco and have a membership....then the Coscto Tier II fuels are great.  SO....fill up that rascal and drive it.  You want to drive for maybe 100 miles...then you can safely park it....
NOW the rest are a bit OPTIONAL.... You do NOT need to do the Techron cleaning and conditioning every fillup.  I would do it Annually....and DRIVE IT...
HEET or STP Gas Treatment.  You large tank (presumably) will provide the perfect conditions for condensation.  Ethanol fuels, in my esperience and talking to many small engine mechanics and also running a large portable emergency generator are prone to water or MOISTURE buildup.  Whatever the dosage on the container.....add 50%.  That is an alohol based product.  The alcohol allows the moister or water that would condensate and collect to dissassociate and is broken down then it just passes through.  The 5 OZ container treats 20 gallons....so that would be 1.5 containers per 20 gallons.  I would DO THAT AS WELL....that way if there is any water in the tank...you get rid of it...   Buying the single cans is $0.25 per OZ compared to the case of 24 for $80 as that is $0.29....  As with the Techron....do this once a year.  However, I actually use the Stabil and Heet for all my fuel that I store for the generator....
The rest is whatever....Stabil is CHEAP and does good work.  Use it EVERY FILLUP...Buy in bulk from Amazon.  SO, if you added Stabil and Heet (STP) every fillup....that would probably be great and then do the above for an annual....FUEL treatment.
Past that.... Seafoam is recommended.  Starbrite Startron is also recommended.  The Stratron is an enzyme cleaner....usually when you have an issue...or as a OMG, try this.. as we have some critters growing in the tank...  It is a "Polisher"... I think the Techron &.or that is my take.  
The other thing....change the oil annually....whatever brand and grade that has been used....do NOT change....A MUST DO...
 

OK....logically, which rarely applies to a Monaco Coach... LOL.  
Hopefully some 05 to say 07 Diplomat or Endeavor owner with your 40PDQ floor plan will chime in and tell you WHICH switch to look for on your switch panel or where you turn on these lights.
But, you can also start to do the leg work.....Here is a link to the wiring diagrams for your MH.... The last one has most of the drawings...but as usual, Monaco is more interesting in detailing the phone lines, should you need to have a home phone box installed for the MH when you are at home, than the switches for the interior lights.  BUT, trust me...you WILL become best friends with these drawings.
OK...is there one light switch that has no function....for instance the lights that do not work?  As stated earlier, you need to know WHAT switch as well as other lights come when the "switch" is turned on.  
NOW, if you REALLY can't find the missing other end...and using a bore scope is a good idea...but usually you can remove the panel or wooden plate that the lights are mounted on or find a way to take down some of the interior panels inside a cabinet.  I have been able to get to the back side of most of my fixtures.  So, I would start looking.  Monaco sometimes used screws....other times a "finishing nail" or pin gun.  Gently prying on a corner of where you see the "Molex" plug and getting in there and being creative is the best advice.  Others have done this.  Maybe someone will chime in.
OK...did Monaco not run the mating connector?  Possibly.  ODDS ARE...it is there, but did not make the trip inside the cabinet or the raceway (side panel) of the cabinet.  I would search for that.  Next up...you COULD get a Toner or a signal generator and then tone or chase out the wiring.  BUT, you HAVE to know WHICH Switch controls it and then put your tone or "pinging" lead on that wire...then use the receiver and start checking the inside of the cabinet or above them.  THAT has been successful...don't know if the wood will block...but it is an option.
Finally....PUNT.  The simplest way....if all else fails.  Purchase a small wattage 120 VAC to 12 VDC power supply.  Check the wattage and number of bulbs and do the math to get the right wattage power supply.  Mount that in the cabinet above the Microwave.  You will have to get a "splitter" or a 120 VAC Y adapter to get power and use the Microwave circuit.  Then start removing the interior side panels of the cabinets between the Microwave and the "I ain't got NO power" Molex.  Run the power over and then install a switch and drive on.
All sorts of options.  Since it has been TWO years...think a little.  Depending on USE...have you thought about a battery powered LED for each area...  Way less trouble and the ones you can focus or move the head or the spots around are nice.  My wife had me put on in the bedroom as the overhead puck, for reading, did not give sufficient light...so there is a battery powered one double stick taped in the corner.
Good Luck...but at least NOW you have the prints....
 
 

Look at the print.  This isn’t a control device for a NASA space capsule surface cooing system.  The closer to the Magnum/Inverter, the better.  Use the temp range on the print.  Mount it where is will react or measure the encapsulated or dead air in the bay.  

Here's the skinny.  I started this earlier buy had to run a LONG errand.  Your MH has a BIRD (BiDirectional) charging system.  See the print below.  I wanted to verify that before I posted.  The way it WORKS..  You have the Big Boy (largest Solenoid in the Rear Run Bay or where all the "electric stuff" is.  That Big Boy does TWO things.  First, it is supposed to allow you to charge EITHER (BOTH) sets or banks of batteries when you are on SHORE (Genny as well) or Engine running.  It is controlled by a Board in the rear.  If you ready your manual, you will see a photo of this area.  I am enclosing a print of it from the 2005 Wiring Diagrams.  I urge you to download the following file as anytime you have someone work on it, they need these.  YOU MANY already have them in your manual, but manuals have a BAD habit of disappearing.  It is ALSO easier to give a tech an electronic copy than for him to be fritzing around and finding the prints. 
SO, follow along.  In the print below (38041334...), the Big Boy is in the center.  I has TWO large cables connected to it and two small ones.  The ones on the bottom side are hard to see.  That is a 200 Amp Solenoid.  It has TWO purposes and BOTH are controlled by the R6 Board on the right.  The first is to be used as a BOOST.  When you push down and hold (it is spring loaded) the Battery Boost switch, then that solenoid goes CLUNKL and closes and it starts to heat up.  The OTHER thing that the R6 board does is to ALLOW FOR BIRD (both Ways) charging.  So, driving....Alternator is putting out current (or Voltage if you like).  That charges the CHASSIS.  When the Generator or Shore is ON, the Inverter charges the House.  BUT, if the OTHER set needs charging, then that Solenoid is energized.  IF you hold down the BOOST Switch up front for more than say 30 seconds, you are then in the DANGER zone.  That Switch feeds PURE 12 VDC (more likely 13 - 14 if charging by the Alternator of the House.  That will start to BURN UP the coil.  It is NOT rated for full (12 - 14) VDC....for more than say 30 seconds.  Some folks don't know this and have damaged the Big Boy by listening to some "saw it on the NET" advice.  
NOW....  BUT, you say....how do it CHARGE BOTH (Closed) sets of Batteries without burning up?  Simple, the R6 Board sends out a PULSED 12 - 14 VDC.  I do NOT know how many PULSES per second....an Oscilliscope might tell...but it cycles ON and OFF maybe 50 times per second.  OK....1000 (milliseconds) divided by 50 equals 20 Milliseconds per PULSE.  Remember it OPENS and CLOSES or think about flicking a light switch ON and OFF 50 times per second.  NOW...you need to UNDERSTAND what PULSE WIDTH or DURATION is.  If there is a 20 MILLISECOND pulse...and the ON time is say 13 Millisecond and the OFF time is 7 seconds...then if you put a DVOM on the two small terminals, you would "read" around 8 VDC (or about 1/3 less than the 12 - 14 Second PURE, ON AT ALL TIMES, DC.  So, when the R6 board is regulating or sending out a PULSED signal to keep the Big Boy Energized....that reduced (effectively) voltage is lower.  The FIRST pulse when the R6 says....LETS CHARGE BOTH is a PURE 12 - 14 VDC signal...say for a full second.  That ENSURES that the Big Boy is locked in or energized....then almost immediatly, the signal drops back to the PULSED (1/3 OFF and 2/3 ON) so the Big Boy can run ALL DAY or night or 24/7 and NOT be damaged.  When the PULSED signal is used....the Big Boy starts to CHATTER or HUM...Loudly.  It gets HOT to the touch (maybe 140 DF) but it is quite content to run that way.  Thus you get Charging from one side to the other...as the Contacts (BIG ONES) inside are closed..
NOW....here is what you need to test...  Have someone PUSH the BOOST Switch.  Put your hand on the Big BOY...Did you feel it CLOSE or CLUNK.  That means the boost switch and the R6 Board WORK OK.   THEN you have to take the NEXT STEP.  Turn ON your headlights for maybe 10 minutes or even 5.  You SHOULD be plugged in to Shore or your Genny ON.  You should FEEL (lightly touch) the metal can.  If it is chattering or humming and is HOT, it be WORKING.  It SHOULD be trying to close to let the Invterter CHARGE the Chassis as they are being drained.  NO HUM...or HEAT.  Coil is shot.  Nothing can fix that...
BUT, if it HUMS and heats UP...then you need to measure across the LARGE Terminals (Studs).  Put your DVOM into DC voltage.  Put the probes on each of the TWO big studs.  You should SEE ZERO or maybe Less than 0.05 (not 5/10th) VDC.  Use the Ohm setting and do the same.  If there is an OPEN circuit...the Big BOY (assuming it is humming and getting hot, needs to have the Contacts cleaned.  A simple job and there is a HOW to in the files plus a bunch on YouTUbe.  Many folks do that without being an electrical engineering graduate.
NOW...if all that fails and you DO NOT heat the humming nor the coil is getting HOT, then you have to carefully loosen all the bolts and take it partially out.  You THEN put an Alligator Lead to the small terminal hidden on the bottom.  Just lay the Big Boy back in place.  Do the Headlight DRILL again....if you read around 8 VDC when you measure from the Alligator Clip (attached to the bottom small terminal) and the TOP small one....the BOARD (R6) is working...
HERES the bad news.  Those boards are NOT in production anymore and the used ones are usually broken.  There are a few folks here that can, on occasion, fix them...and it is an ART and they have special equipment.  The one vendor that "Supposedly" could fix them has a spotty track record and they don't really know HOW to remove the defective chip and put on another one.
You have to find a REAL tech with a background in Monaco and Intellitec (the vendor that makes the Big Boy as well as made the R6 and a HOST of other boards all in the front and rear of your MH) system.  They need to properly diagnose (like I described) above...and THEN, if they say...I can get it fixed...pay with a credit card and be prepared to dispute the charges as it ain't gonna work...or the likelyhood is low....THAT IS A FACT.
NOW, there are MANY options.  I wrote this up in at least TWO topics....both are below the prints.. READ IT...
Bottom LINE...you can INSTALL, if the R6 Board is Dead...a Blue Seas ML-ACR.  They run a bit under $400.  Fairly simple and many have done it.  The downside....  You do NOT have enough "wires" running from the BOOST Switch for it to work.  If you get the simple one or the basic Model...without the REMOTE, it comes with a ON, OFF and AUTO switch on it.  If you EVER need to use the boost switch...you just open the door, walk back and open the RRB and turn the switch to ON.  The batteries are connected.... Then after that need is passed...you switch it back to AUTO and it charges BOTH Banks, but does NOT charge when one set of batteries is acting funky or are weak, so you don't run down a good set (like pouring money in a hole in the water).
NOW, if you decide to go "BIG TIME" and get the Remote....then you can do it simple or complex.  Simple is to only have the Boost Switch up front working.  You have to rewire the switch so that the SIGNAL is 12 VDC (Positive).  The switch is now a GROUND (momentary ON) switch.  Then the Boost Switch will close the ML-ACR and you have boost.  The ML-ACR is rated for 350 amps vs the Big Boy for 200 A.  So...that is is.  BUT, if you want all the bells and whistles, you have to put at least 3 wires or 5 to be safe and have a spare or two) from the FRONT to the REAR...and then you can mount the remote up front.
There are OTHER things, that folks do...and maybe one or two that I would....but let's not get into that.
You need to TEST your system.  HOPEFULLY, Board R6 works....and if so, and the Big Boy can't be cleaned or someone cooked the COIL, you replace it.  BUT, if Board R6 is toast and no one chimes in to assist and fix offline....then put in the SIMPLE ML-ACR and get a little exercise when you need a boost....
Your call...
 
38031334 Rear Run Box - ALL Dynasty & Up Big Boy Information.pdf

OK…
Yes, assuming you have a 4 or 5 button Thermostat and it has data or “phone” cables when you pull down the interior cover and look up, you can replace it with a new Dometic system.  If you have two thermostats, you will need two so it will be an uograde…same for one.
Get the current model numbers from your existing units and take a picture of the thermostat.
Call Lippert and follow the prompts to the Dometic tech support.  I would upgrade a 13.5KW if you have a mixture to a “all” 15KW as my two 15’s are barely adequates for my 40 ft.  It you had ample cooling….your call.  You may not have had heat pump models, but I recommend them.  But, if you live in the deep south and never use or want the HP, then go with the AC only.  The Dometic folks will tell you exactly what you have and recommend the new units and give you the model number and the thermostat model.  
There are “two” different units.  The Penguin II and another one, perhaps with a higher capacity called a Blizzard NXT. We have had folks upgrade or choose these and they say the airflow is better and quieter…. If they have a suitable model in the NON Penguin product line….get those numbers.  They use the same CC2 or new MPX system.  I think they are interchangeable but do not know the price differential.  Now you have all you need.  
I would google “difference between Penguin II & Blizzard NXT.  Here is one resource.  Ask Dometic….
https://www.irv2.com/forums/f54/blizzard-nxt-vs-penguin-ii-298438.html
OK…then get quotes on the series that you elected or both..That’s it…not hard…just laying out the process.  I plan to do that exactly and have a tech already selected when one of mine fails.  I am sticking with the new CCW Dometic thermostat.
That is the way you should handle it.  We have many great posters with a wealth of knowledge, but since Dometic is always changing, I will let them tell me exactly the right models or PN…even though I have notes from a conversation a few years ago and the tech answered my questions to verify my knowledge.  Also explained what I thought I knew so I was confident when I helped others.

This, to me, is really one of those....  Do it with common sense...and there are a myriad of ways and such.  The DiCor site does NOT have the instructions or the installation (Page not available)....  Fantastic Fans had a recall and provided a new dome and all the fixin's to put on the new dome and replace the gasket as well.  
My take is that Alcohol (plain old low percentage rubbing) and a cloth will and was what, memory, Fantastic Fan recommended and they did several installs in their shops and wrote the instructions.
Denaturized alcohol will also work.  Ain't a heck of a lot of difference.
Acetone (Blasphemy) also works...but one has to understand that one must be outside and should not pour a can all over the roof.  I have been fixing seams and recaulking since 2006 and I worked in a boat factory making boats and we had enough Acetone for a massive explosion on site.  We, the grunts, never had an infection in a cut or puncture from a glass fiber impregnated with resin because the Acetone kill all the bacteria...as does alcohol.  I have used acetone to clean off the top surface of where I was going to caulk or recaulk for years.  
Lacquer thinner.  Now that is a little TOO Potent.
Paint Thinner.  NEVER...or at least for me.  It does NOT flash off and dry and you run the risk of the sealer pulling up.  Ever painted over a surface that was clean, and not allowed to air dry for 24 hours with paint thinner.  The result is not pretty...so I would NEVER, not even in a pinch, use it.
The MAIN thing...  Wash all the area with a good cleaner.  I use Simple Green with a small portion of Bleech White (tire cleaner...and potent...but diluted) and a shot of Dawn.  Then thoroughly rinse. IF there is evidence of mold or mildew...I put in maybe 10% Clorox to kill the critters.  AGAIN RINSE.  
After it dries, then one of the above (plain alcohol or such...).  NOW, if it still looks crappy and I am covering the old caulk...I use Acetone....sparingly on a cloth and apply it with that.  For a really deep crevice, I will splash a little on and scrub with a toothbrush or parts cleaner.  I often use a good stiff parts cleaner (fiber) bristle brush to clean.
Obviously, peeling or scrapping off any loose.  I use a razor knife to cut a little past where the peeling is so I can pull it up and get a clean edge that is bonded to the roof. I have never nor would I intend to peel up all caulking.  If it is bonded....it is crosslinked.  
BUT, I also recoat or cover the old as I know it has crevices or voids or air bubble below...I can see that when I rinse as I push down to test.  
I always use blue painter's tape to mask off and such.
I realized that you, Steven know all this, but I tried to answer your question with my experience and knowledge...but others may not have gone through it.
That's how I do it and it works...

Basics...  Read the Paper in the file on Battery 101. 
Specifically, get some safety glasses (over your specs if needed) with the wrap around or sides covered.  Wear old clothes or you can "age some jeans" and sell them.  Use Latex gloves.  OK...
Next.  I would consider doing a few things BEFORE I started taking things apart.  If you have a Pull Out Battery Tray....then pull it out...and it should have a DRAIN.  If not and you have to lift and set the batteries in place, then order a "battery" lifting strap ($5-$10 - Amazon) or find one locally.  Basically a strap with two hooks and you have an indent or place to put it on each side of most batteries.  WAY EASIER AND SAFER.
So, take Pictures...  LOTS and also use some blue painters tape and mark where the positives GO..  Use another color or Masking tape and mark the Negatives with that....to keep them separated and so you can reassemble.  Do the same for the Chassis as well.
NOW pull out the batteries.  Mark them and I would also put them back into the same "locations".  Not critical, but good practice.
On a surface (put down plastic and have it drain to somewhere, NOT a nice grassy spot, and gently wet down the top of each.  Use a poultice of Baking Soda and enough water so that it is thick..and can be brushed one with a small brush or poured on (pancake syrup style).  Then neutralize the acid.  takes only a minute and when the fizzing stops...gently RINSE (not high pressure wash) the tops.
The WINGIE things are the cell caps or covers.  They rotate one way and that releases that entire cap.  In your picture, the vertical tab or lever on the outside...push it towards the POSTIVE terminal...and it (the entire assembly) lifts up.
NOW....You WILL NEED some Distilled Water (Pharmacy or anywhere they sell Bottled Water)  NOT SPRING or TAP water.  Next...you need a Syringe or a small funnel...  A drinking water bottle with a FLIP UP and DOWN Cap works great.  The TRICK is NOT TO OVERFILL...that LOOKS like the issue...and I was guilty...
OK...next up, you need a 1/2" or 3/8" hardwood dowel...maybe 8" long and a knife and a Sharpie and a tape measure or 6" scale.  
FIRST....  Insert the dowel (battery sitting on fairly level surface) and let it rest or drop down to the plates.  Mark the SIDE of the dowel at some reference point...like the top or the top of the cell...it depends on how your battery is made.  NOW, use a good flashlight and shine down into the cell.  Start to LIFT the dowel, slowly and STOP when the bottom of the Dowel is flush with the "well" or the sunken place.  The well usually has side slots and a bottom.  Get the dowel up and stop when it is flush with the bottom part of the well.  MARK the Dowel again. Wipe off the dowel (paper towel and it IS acid...so have a plastic container for them).  Measure the distance between the two marks...to the nearest 1/16".  ADD ONE sixtenth to that...so it if was 7/16....make it 8/16 or half an inch.  NOW, measure UP on the Dowel from the end.  Make a Sharpie Mark there...in my example...1/2".  Then take the knife and SCORE a small groove around the dowel....NOW, you have a BATTERY DIPSTICK.   From NOW ON....you always FILL to that Mark and NEVER OVERFILL.  That will eliminate your leaks and keep your batteries clean.
Go back to the BOX...clean the terminals with the Baking Soda... maybe have a plastic bowl in there to keep from spattering.  You can then use a cloth with the baking soda poultice on it and wipe out the box.  Use a cloth and rinse...  See if you need to wire brush or sand and paint.  Rustoleum Primer and then Rustoleum Pickup Truck Bed Liner works great.  I would clean the surface with some ACETONE first and let it dry for an hour of so...Then use the Primer....wait (see the can) and then coat with the BedLiner (read the times) and put on at least 2 coats. 
You MIGHT need to order a hydrometer from Amazon.  EZRED SP101 Battery Hydrometer
https://www.amazon.com/E-Z-Red-SP101-Battery-Hydrometer/dp/B000JFHMRU/ref=sr_1_5?crid=2NN79PRMQ5Y4Z&keywords=hydrometer%2Bfor%2Bbattery%2Btesting&qid=1692805684&sprefix=hydrometer%2Bfor%2Bbatt%2Caps%2C91&sr=8-5&th=1
When you use it...there is a cast in (plastic housing) line at the TOP.  FILL ALL THE WAY UP and hold it level.  It also makes a GREAT suction or pump for getting out excess (I over filled at time or two) tool...you can REUSE the electrolyte in an adjacent cell if you goof.
Order a spray can of Battery Anti-Corrosion and then thoroughly coat the terminals and the nuts when you reassemble.  Then, check the batteries twice a year.  Battery 101 also tells you how to exercise if you don't run for a while off the inverter.
Class dismissed....Have at it...

@Lenny D  edited…found one….
 
There you go.  Tan/Brown ain’t out there.  Hereare the PN for replacement.  Too HIGH.  Start with the Black.  I found the OOS white for $15 and in stock by googling…it is a “prostitution market”.  Keep looking.  
NOW…the other option is Northwest RV Supply.  They boight tons of Monaco inventory.  Call or email them.  They may have them or try ebay.
The key goggle phrase is Dometic RV temperature (temp) sensor cover.  That is how I found the PN and had copied the white and found the $15 OOS 
EDIT
https://rvpartsexpress.com/product/dometic-3313107-064-sensor-cap-white/
IN STOCK..$22
Buy the whatever color you can find… Choose a spray can color you like.  Be proficient with a spray can and spray the sucker….will last for years.
That’s how I would do it.

Late coming in.  First.  All the information is covered in the chassis section.  Since you have some questions about some of the more Fundamental things, might be a good time to scan the manual,
On page 197, there is a complete description of your air system and the brakes.  Specifically on page 200 is the diagram and “how to “ instructions.” On how to use the compressor to inflate items. You might also read the entire section and review the air brake system….as well as the recommended annual or semi annual bleeding and looking for moisture….which is a sign that the desiccant air  filter cartridge in the rear needs changing….very important.  Not doing this can result in water in the braking system….possibly impacting its performance as well as a super costly repair.
The other picture is the regulator that controls your air seal or the speed operated valve that inflated the bladder seal and shuts out 90+% of the road noise that wraps around the entire inner door frame.
DO NOT TURN THE REGULATOR VALVE.  It has been factory adjusted to a very low air pressure and you a need precision gauge, not just a common tire pressure gauge to recalibrate it.
I  great that you asked and posted pictures….and all these are covered in varying levels of detail, some really COVERED, in your manual.
hope this helps.
@camelot
 
PLEASE DO NOT DO THAT….read my post. If you do then you will run the risk of bursting a seal that was part of the entire door frame and there are no, based on many folks experience, new replacements…

OK...from the TOP.  This, hopefully, is the same as your 2006.  Whoever did your solar should NOT have had or needed to "mess with the transfer switch".  I say that based on what I know about the electrical systems on a Monaco as well as verifying on the prints.  Look at the one I attached.  Also here is where I got it.  If you ever need a resource, then SEARCH for it.  You can put something like WIRING in the search box at top right....and then click on EVERYWHERE and choose Files.  That is how I got these...I usually have a copy on my laptop...  Then I saved a PDF of the Main 120 VAC print.  The BLOCK diagram at the bottom shows Line 1 and Line 2 coming in from the Generator and the Shore exactly alike.  You need to get a qualified electrician to remove the cover from the ATS and chase down and reconnect the Generator LINE that is missing.  NOW, you may have a defective Circuit Breaker in the Generator....not likely.  That is a Dual, side by side, Circuit breaker.  I'm guessing that is is a 25 Amp rating....as in you are protected or "fused" at 24 amps on each leg.  
NOW...your questions...  ONE...NEVER should have disconnected one leg.  PRINT proves that...
TWO - YES....but with a Caveat....It is a matter of WHAT you want to do.  You have a total of about 50 TOTAL amps of power from the 5.5K Generator.  THIS IS NOT THE SAME AS 50 AMP service.  When you are on SHORE, Line 1 and Line 2 BOTH have 50 AMPS EACH....On generator, you only have 50A total...and they are split evenly.  You have 25 amps on Line 1 and Line 2 from the Generator, as it was ORIGINALLY wired...and should be...or maybe I missed something and we have a LOT of smart folks here.... 
OK...understand the loading.  Your Air Conditioners (Heat Pumps?) will run around 15 Amps or so after they start up.  Therefore, 25 Amps (if I am correct) will easily run ONE air conditioner.  BUT, you run another device...like your batteries are LOW, then the Inverter/Charger can pull as much as 15 Amps.  OPPS....overloaded the one line.
Look at your prints.  Line 1 powers the Front AC.  That also has some INTERNAL outlets and the Water Heater.  So, you can NOT run the Front AC and use the Electric element of the Water Heater.  That is a total of up to 40 amps.  YOU ONLY GOT 25.
NOW the rear is even trickier.  If you run the REAR AC, it will pull maybe 17 from time to time.  BUT, there is a 30 Amp breaker for the Inverter/Charger.  BIG TIME OVERLOAD....you only have 25.  SO, you would have to TURN OFF the CHARGER when you were on Genny....That will NOT WORK..  I suspect some "enterprising, but UNKNOWING" tech did not understand...and decided to "Shade Tree Wire IT".  Your Owner's manual may NOT go over this.  IF your panel is the Smart EMS (Optional), then you have a Load Shedding device and your AC's are going to be on and off like popcorn kernels popping. 
NOW, if you do NOT have the EMS, the WIRING is the same...except you MUST do your own load management and NOT OVERLOAD it.
With LOW house batteries, you MUST recharge them FIRST.  Then, turn OFF the Charger section of the Inverter/Charger.  NOW all the inverter is doing is passing power through (from the inverter) to your House Outlets.  You can run THEN turn on the REAR AC.
While all the above is going ON...You can RUN the front AC.  It is on a different line.  BUT, if you plug in a high demand item like a hair dryer, coffee maker microwave or space heater....BINGO, you are gonna trip a breaker.  MOST LIKELY the one on the Generator...
SO, you MUST understand that on Generator, you only can use 25amps or so...and if you exceed that on EITHER LINE...it is gonna cause issues.
That's it.  May be confusing...may be simple.  BUT you have an improperly wired Auto Transfer Switch.  It needs to be restored per the PRINT.  If you have the EMS, it will do, assuming it is working and no one has gone inside it and "messed" around.  If you do NOT have the EMS...same deal...but you have to be the BRAIN to load shed.  
BUT, you can NOT run BOTH AC's without making sure that there is nothing but a light load on either of the other two circuits.  Line 2 is your Charger/Inverter.  It really draws NO CURRENT when it is NOT charging.  It is passing through the Generator (shore) power.  
Think upon it.  Ask questions.  Good Luck
Download these prints if you manual does not have them in the back.  EVEN so, I would have them as an electronic copy to print for a tech.
 
2005 LaPalma main panel and generator Wiring Diagrams.pdf

https://www.thetford.com/product/aqua-magic-bravura/
On that link you will see MANUALS.  Click on the Owner's Manual.  Mine is a different model, but the owner's manual is the same.  Look at the end of the part's list.  The "shroud" (high rise or low rider....Like the CA cars) depends on whether it was an ADA or regular height.  Reach around behind the shroud.  There is a big "O Ring" or like a big hair band.  There are two ears on the shroud.  You just "Stretch" the Oring...and then lift if off the tab or ear.  Then the other side.  May take a little "jockeying" to get it to slide over the pedal assembly.  There are TWO bolts with nuts.  These bolts are actually "J Head" in that they fit down into the fitting in the floor.  You can tighten...but do it carefully.  The "J Head" of the bolt fits into a slotted groove...with a round hole at the the end.  You drop the bolt down into the round hole and slide it to fit the toilet.  These slots are long and curved....so it is doesn't matter how Charlie the plumber set in or put in the bottom flange.  Tighten each one only 1/16 or 1/8 of a turn....don't crank down on one a few turns.  You MAY find one side is loose, so get that side (feeling the amount of torque or force on the wrench) to match the other one.  Then gently snug each....going slowly and stopping.  This is how the "Stinky Seal" between the toilet and the flange is compressed.  
BTW....if you click on the OTHER link, there are TWO kits.  One is a seal kit which replaces the O-Ring in the bowl where the ball rotates and also the stinky seal.  You remove the toilet and put in a new stinky and then the bowl seal.  Get a small container of Plumber's Silicone Grease for Lowes or HD or hardware store.  Grease the O-Ring that you see from the top about once every 3 months.  Slather on a coating of the silicone on the ball surface.  It will seal better and less chance of leakage.
The other kit is the FLUSH kit.  They only, rarely, go bad....like when the rig is not winterized and it freezes the water.  BUT, they do sometimes leak.  Replacing it is a piece of cake once OUT.  It only goes one way.  Your camera is your friend before you start to loosen any screws or take off any levers.  If you have to pull the toilet, get a can of Garage Door spray grease (White Lithium).  Fill a small cup (like the meds cup a nurse brings you at 3:00 AM and wakes you up to take a sleeping pill).  Then use a Q tip and put some grease on where the levers and such move in the valve or where the ball pivots or where the pedal linkage moves.  
That's it....  Gloves are recommended for old rockers that probably have callouses on their fingers....or small cuts...

On my Camelot....and I THINK many other models, including the Diplomat....have a 160 Amp Alternator. There were a few earlier NON Dynasty....maybe a few models of the Windsor, that have the upgraded 200 Amp LN.  All Dynasty and up have it unless the higher, very high ends had a 240 or maybe a 260 A model for some engines and maybe an ALL ELECTRIC MH....
I have the LBP-2180 and/or including the LN info....110-912.  The Regulator for it is the LN Regulator number 8RG3078 or maybe 8RG3102S....
Doing a search for it and such provided the following. Show the pictures and how to install and it appears to be an external attached, but is internal. Note the "hole"
https://www.elreg.com/wp-content/uploads/pdfs/8RG Regulator Change Out Procedure .pdf
OK....I THOUGHT it was NOT adjustable....but then kept digging.  IF I have the 8RG3078 OEM Regulator, It IS adjustable, but it does not look like the one in your picture or used on the Monaco Models (LBP Series).  That Regulator 8RG3078S maybe or supposedly came with the OEM, but I could not verify that on the LN site.  
https://www.peivinlookup.com/Category/8RG3078S/Alternator-Voltage-Regulator
There IS an alternate Regulator or "Leece Neville DIRECT REPLACEMENT....that will also work and is sold for the LBP series....IF I read correctly. it is the 8RG3102S.  IT IS NOT ADJUSTABLE.
https://www.peivinlookup.com/Category/8RG3102S/ALTERNATOR-VOLTAGE-REGULATOR/Alternative
So, I guess it depends on which regulator is on the LN LBP (mine is the 2180 or AKA 110-912) that one has....and they look identical, except the hole on the 8RG3102S is a "Fake" or used when they use that housing for the adjustable one. 
Bottom LINE....one must have the correct PN info....which is available on the build sheet and should be verified from the Alternator....then also determine WHICH regulator that it is.... Here is the LN current listing for my alternator....it does have the external, bolt on Regulator, but there are TWO different versions....and you must know WHICH you have.  They look the same....as they use the same Regulator housing.  I did not do a screen shot as I have two monitors and get BOTH screens.  Click on this....there are several photos of the regulator, which I know, look like mine from my cursory inspections...
https://prestolitesuperstore.com/Category/LBP2180GH/Prestolite-Leece-Neville-LBP2180GH-New-Alternator-LBP-Series-Pad-Mount-type-12V-160A 
That's what most of the LN alternators used on the Monaco's should look like....Hope this helps and ties down what we are discussing....