No 12 VDC Power in 2005 Ambassador - 120 VAC OK

[saflyer]

Edit.  Revised Topic title to state the issue more clearly. End of edit.

We came back from a day at the beach to find none of the 12v lights or devices work. All 120v items like lights and microwave work. The surge suppressor shows power from each leg of the 50a shore power. The EMS panel doesn’t have any lights illuminated but, like I said, all 120v outlets work. Is there some main 12v fuse that may have blown?

Earlier in the day we had a problem with the leveling jacks. I was going to adjust them. The front jack switch stuck in the extend position and might have gone to it’s limit. After retracting it some none of the legs would extend, only retract. When I try to get any of the legs to extend I hear some sound from the lower front electrical bay and at the hydraulic pump but not the sound of its running. Could there be a connection.

Ed          
‘05 HR Ambassador

[WayneC]

Sounds like a solenoid weekend, finally returned to the coach after 5 months,changed starting batteries, 5 years old,they were low on voltage so just switched them out,changed one solenoid in engine bay in July, I seen today when going through the parts totes that I have 3 more brand new ones,in saying that I am going to change the one on the other side in the morning,  I also have no 12 volt power, 120 good, inverter will come on ,TV and so on will work.

Guessing that may be the problem your facing, a friend of mine was the previous owner ,he would be back there taping them with a hammer, I bought a few spares.

Will let you know how I make out

Wayne

1999 Signature ceaser 

 

[MyronTruex]

See if you can start your engine to allow the alternator to supply 12 volts to the house batteries. 

 

Leveling jacks would be 12 volt most likely.

Your converter/inverter may not be charging. 

Go to your AC breaker panel and see if any of those breakers feel mushy. 

 

[saflyer]

My house batteries are not charged from the alternator. I disconnected that function when I installed lithium batteries. Will be adding a DCDC charger in the future. The house batteries are being charged from AC through the charger/inverter. It indicates charging correctly.

[Dr4Film]

"No EMS Indication", I am assuming you are referring to the Intellitec EMS System that sheds load when hooked to shore power less than 50 amps.

That EMS is powered by your 12 VDC system. I would assume that you don't have ANY 12 VDC available to any devices, correct? If you do, then i would check the fuse on your EMS control board to see if it has blown.

If not, then you need to look at your 12 VDC Battery Disconnect Solenoid providing that you didn't accidently hit the "Salesman Switch" by mistake.

[kenandjoanne2002]

I look for the simplest way to fix everything.  I have had a dead EMS several times.  I go to the converter bay, unplug two telephone type connecters, give them a shot of electric cleaner spray.  99% of time my EMS panel is working properly.  Ken Parsons 02 Dip

[saflyer]

59 minutes ago, Dr4Film said:

"No EMS Indication", I am assuming you are referring to the Intellitec EMS System that sheds load when hooked to shore power less than 50 amps.

That EMS is powered by your 12 VDC system. I would assume that you don't have ANY 12 VDC available to any devices, correct? If you do, then i would check the fuse on your EMS control board to see if it has blown.

If not, then you need to look at your 12 VDC Battery Disconnect Solenoid providing that you didn't accidently hit the "Salesman Switch" by mistake.

Yes on the Intellitec Smart EMS and no 12v devices work anywhere including the propane detector. The main switch panel where the tank level test, water heater, slide operation switches are located is inactive except for chassis battery voltage test. The roof air control panel has no power either. 

I checked the  salesman switch. I believe it is reset by pulling out on the bottom of it, am I correct? (At one time years ago I intended to eliminate it if it used power to stay closed but eventually decided it didn’t draw from the batteries so I left it operational. Wish I hadn’t.) I cycled the house battery disconnect and checked it for continuity. It’s good.

That’s what I know so far.

[Dr4Film]

Bypass the Battery Disconnect Solenoid(s) and you should be good to go!

It won't happen again.

Edited February 20, 2023 by Dr4Film

[saflyer]

28 minutes ago, Dr4Film said:

Bypass the Battery Disconnect Solenoid(s) and you should be good to go!

It won't happen again.

Where are they and what do they look like?

[Dr4Film]

Not sure but most coaches have it in the Rear Run Bay.

I am not familiar with the layout of your 05 Ambassador.

Posting a photo of your RRB would help.

[MyronTruex]

13 hours ago, saflyer said:

My house batteries are not charged from the alternator. I disconnected that function when I installed lithium batteries. Will be adding a DCDC charger in the future. The house batteries are being charged from AC through the charger/inverter. It indicates charging correctly.

Looking at the schematic for a 2005 Ambassador it looks like you have the (salesman solenoid) inside the panel below the driver in the outside compartment.

You need a voltmeter to begin taking some measurements there. You could easily have a bad solenoid. There is also a small breaker in that area.

One of the large round binding posts in the area will be the negative to use for your voltmeter or even a cheap test light.

You need to get a measurement on each side of the solenoid in the bottom left corner inside the box. You should hear the solenoid clunk when you cycle the switch but that does not ensure it is actually working properly.

 

Pictures will indeed help as Richard said. 

 

 

Edited February 20, 2023 by myrontruex

[Tom Cherry]

1 hour ago, kenandjoanne2002 said:

I look for the simplest way to fix everything.  I have had a dead EMS several times.  I go to the converter bay, unplug two telephone type connecters, give them a shot of electric cleaner spray.  99% of time my EMS panel is working properly.  Ken Parsons 02 Dip

Not knocking your statements, but the Intellitec EMS that monitors your 120 VAC power and sheds the AC loads is not, any way, shape, form or manner connected to the Inverter.  The Intellitec EMS is located behind the cover of your main AC panel where the circuit breakers are.  It has a single communications line to the EMS a remote…which is probably mounted near the Inverter remote.  The EMS remote is totally DUMB.  It does have one “task” it can perform.  You can push the 20 Amp button and toggle it between 30 amps and 20 amps depending on the source of your power.

The correct way to reset the Intellitec EMS is to KILL the 12 VDC house power to the printed circuit board.  Disconnect the battery or turn off the house battery or turn OFF the Salesman Switch or remove the cover (AC off) and unplug the connectors and pull the 3 amp fuse.  That usually works.

The telephone cables that are connected to your inverter are for the remote and probably the Battery Temperature sensor.  This is generic for all the inverters that Monaco installed with a remote monitor.  On the Magnums, with an AGS, there will be 3 cables.  That is strictly communication like the cables from a monitor or a printer to a PC.  

2 hours ago, Dr4Film said:

"No EMS Indication", I am assuming you are referring to the Intellitec EMS System that sheds load when hooked to shore power less than 50 amps.

That EMS is powered by your 12 VDC system. I would assume that you don't have ANY 12 VDC available to any devices, correct? If you do, then i would check the fuse on your EMS control board to see if it has blown.

If not, then you need to look at your 12 VDC Battery Disconnect Solenoid providing that you didn't accidently hit the "Salesman Switch" by mistake.

Maybe on the fuse, but not likely.  When there is no 12 VDC in the system and/or the Salesman Switch is off and/or a defective Salesman switch solenoid, there will be no 12 VDC to the Intellitec EMS.  It will be dead.  The AC outlet are fed from the Inverter.  The HVAC will not work as the 12VDC Powers the controllers in each so the Thermostat has no power.

[saflyer]

28 minutes ago, Dr4Film said:

Not sure but most coaches have it in the Rear Run Bay.

I am not familiar with the layout of your 05 Ambassador.

Posting a photo of your RRB would help.

Having a brain hitch. Where is the rear run bay? 

1 hour ago, saflyer said:

Yes on the Intellitec Smart EMS and no 12v devices work anywhere including the propane detector. The main switch panel where the tank level test, water heater, slide operation switches are located is inactive except for chassis battery voltage test. The roof air control panel has no power either. 

I checked the  salesman switch. I believe it is reset by pulling out on the bottom of it, am I correct? (At one time years ago I intended to eliminate it if it used power to stay closed but eventually decided it didn’t draw from the batteries so I left it operational. Wish I hadn’t.) I cycled the house battery disconnect and checked it for continuity. It’s good.

That’s what I know so far.

I’ll note also that the Magnum remote for the inverter is working and shows batteries charging.

13 hours ago, saflyer said:

My house batteries are not charged from the alternator. I disconnected that function when I installed lithium batteries. Will be adding a DCDC charger in the future. The house batteries are being charged from AC through the charger/inverter. It indicates charging correctly.

The house batteries are being charged by solar as well.

21 minutes ago, Tom Cherry said:

Not knocking your statements, but the Intellitec EMS that monitors your 120 VAC power and sheds the AC loads is not, any way, shape, form or manner connected to the Inverter.  The Intellitec EMS is located behind the cover of your main AC panel where the circuit breakers are.  It has a single communications line to the EMS a remote…which is probably mounted near the Inverter remote.  The EMS remote is totally DUMB.  It does have one “task” it can perform.  You can push the 20 Amp button and toggle it between 30 amps and 20 amps depending on the source of your power.

The correct way to reset the Intellitec EMS is to KILL the 12 VDC house power to the printed circuit board.  Disconnect the battery or turn off the house battery or turn OFF the Salesman Switch or remove the cover (AC off) and unplug the connectors and pull the 3 amp fuse.  That usually works.

The telephone cables that are connected to your inverter are for the remote and probably the Battery Temperature sensor.  This is generic for all the inverters that Monaco installed with a remote monitor.  On the Magnums, with an AGS, there will be 3 cables.  That is strictly communication like the cables from a monitor or a printer to a PC.  

Maybe on the fuse, but not likely.  When there is no 12 VDC in the system and/or the Salesman Switch is off and/or a defective Salesman switch solenoid, there will be no 12 VDC to the Intellitec EMS.  It will be dead.  The AC outlet are fed from the Inverter.  The HVAC will not work as the 12VDC Powers the controllers in each so the Thermostat has no power.

If the CO and propane alarms don’t test I assume that rules out the salesman switch, according to my understanding of the manual.

[saflyer]

34 minutes ago, saflyer said:

Having a brain hitch. Where is the rear run bay? 

I’ll note also that the Magnum remote for the inverter is working and shows batteries charging.

The house batteries are being charged by solar as well.

If the CO and propane alarms don’t test I assume that rules out the salesman switch, according to my understanding of the manual.

I tested for continuity across what I believe is the salesman switch solenoid, the black cylinder in the lower left of the image. Checked between the large posts on either side. It showed continuity. It also has a fuse that is good.

Edited February 20, 2023 by saflyer

[Tom Cherry]

38 minutes ago, myrontruex said:

Looking at the schematic for a 2005 Ambassador it looks like you have the (salesman solenoid) inside the panel below the driver in the outside compartment.

You need a voltmeter to begin taking some measurements there. You could easily have a bad solenoid. There is also a small breaker in that area.

One of the large round binding posts in the area will be the negative to use for your voltmeter or even a cheap test light.

You need to get a measurement on each side of the solenoid in the bottom left corner inside the box. You should hear the solenoid clunk when you cycle the switch but that does not ensure it is actually working properly.

 

Pictures will indeed help as Richard said. 

 

 

Odds are….and other Ambassador owners need to chime in, there may/are be TWO Solenoids in the FRB (Under Driver). One is the smaller latching relay.  That is the Salesman solenoid and ODDS are, it has one or two “fuses or fuse holders”.  The other is the battery boost solenoid.  It has NO fuses.  The Salesman solenoid typically looks like this…

https://rvpartsexpress.com/product/kib-battery-disconnect-latching-relay-lr9806c-bip/

Intellitec makes one….there will be a “circuit” or diagram on a Latching Relay.  The Battery (larger) one has nothing.  Both have two large terminals and smaller ones,

the latching salesman solenoid will make a click noise (hear or feel) when it is energized (latched) EITHER away. Have your wide cycle the salesman switch….push top or bottom.  It is OFF or spring loaded to keep it in the middle.  If that solenoid doesn’t click….then it is defective.  You MUST have Voltage coming into a large terminal on the Solenoid. When it latches ON, then you have power to the other.  It is a BIG a switch.  The Battery boost will have voltage on either side as (with BOTH battery disconnect switches on) that is the JUMPER that connects them. 

if one side of the BOOST solenoid is dead….you have a House Power issue….either no voltage or a bad disconnect switch or a loose cable.  It that is the case, then, in theory, you have NO incoming power to the Salesman solenoid.  

do the trouble shooting….. IF you have power on both sides of the Bigger Boost….then you have House power.  Then you should have power on one side of the Salesman solenoid….turn off batteries.  Move the cables on the Salesman solenoid so that BOTH are on one terminal….that should do it 

[Tom Cherry]

4 minutes ago, saflyer said:

I tested for continuity across what I believe is the salesman switch solenoid, the black cylinder in the lower left of the image. Checked between the large posts on either side. It showed continuity.

Yes….if you had moved the black cable to provide a cleaner shot, there is probably a fuse there.  Did you measure voltage?  You MUST have 12 VDC to Ground on BOTH sides or the larger terminals.  The power is coming in from the left side (read the label on the big PCB) and the. The solenoid provides power to the other terminal (looks like the one with the other black cable).  
 

If you have incoming voltage to the left cable and on the right one….then there is a problem downstream and you are going to have to pull prints and figure it out.

BUT voltage on one side and none on the other…the contacts are burned up inside.  Move one wire or cable to another and bolt or fasten them together.

BUT….no incoming voltage of the LEFT side….the time to find your batteries.  Odds are…there is a large ANL fuse (Google it), probably a Bussmann…. It is bolted to a large copper buss.  There may be several others.  That is the main upstream fuse….maybe 80 or 100 amps.  You can look and see the fusible link.  Blown!  That is it.  Do NOT replace with any cheap ANL.  Get an “ignition protected” ANL.  I carry spare BUSSMANN ANL….The cheaper ones don’t last.

that’s as far as I can go…

[saflyer]

18 minutes ago, Tom Cherry said:

Yes….if you had moved the black cable to provide a cleaner shot, there is probably a fuse there.  Did you measure voltage?  You MUST have 12 VDC to Ground on BOTH sides or the larger terminals.  The power is coming in from the left side (read the label on the big PCB) and the. The solenoid provides power to the other terminal (looks like the one with the other black cable).  
 

If you have incoming voltage to the left cable and on the right one….then there is a problem downstream and you are going to have to pull prints and figure it out.

BUT voltage on one side and none on the other…the contacts are burned up inside.  Move one wire or cable to another and bolt or fasten them together.

BUT….no incoming voltage of the LEFT side….the time to find your batteries.  Odds are…there is a large ANL fuse (Google it), probably a Bussmann…. It is bolted to a large copper buss.  There may be several others.  That is the main upstream fuse….maybe 80 or 100 amps.  You can look and see the fusible link.  Blown!  That is it.  Do NOT replace with any cheap ANL.  Get an “ignition protected” ANL.  I carry spare BUSSMANN ANL….The cheaper ones don’t last.

that’s as far as I can go…

To check voltage on each side of solenoid what should I use for ground lead if my meter? 
 

I don’t see any solenoid for the battery boost system but I know there is one.
 

Salesman switch image included. I believe it gives 12v to coach when pushed in at top and disconnects when slider is pushed down and switch pushed in at bottom. Correct? My wife cycled it a few times with no click sound at solenoid. 

Edited February 20, 2023 by saflyer

[Tom Cherry]

Yes….that is the battery switch.
 

Yes..  that is the Salesman solenoid that the battery switch is SUPPOSED to latch or unlatch.  If it doesn’t make a noise…put your hand on the body.  You WILL feel it cycle….it is a mechanical switch.

Did you pull the fuse out of the holder that is hidden behind the black cable.  If it is bad….no click.  Try that…. If it doesn’t click than you are going to have to do some trouble shooting…

There is PROBABLY a ground on the PCB.  But….do it the old fashioned way.  There are hinges on the bay door.  They screw directly into the chassis.  With the point of a meter lead, scratch the head of a hinge screw….then the other lead on the terminals will measure voltage.

NOW….I think you may have larger issues….but here is one more test.  Use the GROUND (screw…or even scrape off a little paint to bare metal on the chassis).  Use that as a ground.  Put the other meter lead (using dc volt scale) on ONE of the small control terminals.  If you have voltage, then test the other.  Should not have voltage….then tell your wife to turn it off.  Each time she pushes it UP or Down, one of the terminals will voltage…the other one NOT.

if you don’t have voltage….then there is an issue….but…at the end of the day….you have GOT to have 12 VDC on both the large terminals for power inside the Coach…

NO POWER ON BOTH….fuse in rear?

POWER ON the LEFT….NO POWER on the right.  Bad solenoid.  Bypass. NAPA sell 781144. That is a jumper

POWER ON BOTH….. LOOSE connection down stream.  May even be the big cable coming into the house fuse.  Find these or get a savvy tech to help…

[saflyer]

40 minutes ago, Tom Cherry said:

Yes….that is the battery switch.  Did you pull the fuse out of the holder that is hidden behind the black cable.  If it is bad….no click.  Try that…. If it doesn’t click than you are going to have to do some trouble shooting…

There is PROBABLY a ground on the PCB.  But….do it the old fashioned way.  There are hinges on the bay door.  They screw directly into the chassis.  With the point of a meter lead, scratch the head of a hinge screw….then the other lead on the terminals will measure voltage.

NOW….I think you may have larger issues….but here is one more test.  Use the GROUND (screw…or even scrape off a little paint to bare metal on the chassis).  Use that as a ground.  Put the other meter lead (using dc volt scale) on ONE of the small control terminals.  If you have voltage, then test the other.  Should not have voltage….then tell your wife to turn it off.  Each time she pushes it UP or Down, one of the terminals will voltage…the other one NOT.

if you don’t have voltage….then there is an issue….you have GOT to have 12 VDC on both the large terminals for power inside the Coach…

The fuse is good. There is 0 voltage to either large posts on the side of the solenoid. I used the frame around the bay door for ground. Of course that may not be a good ground. Any other options for ground in that area.

Also, what is PCB?

[Tom Cherry]

15 minutes ago, saflyer said:

The fuse is good. There is 0 voltage to either large posts on the side of the solenoid. I used the frame around the bay door for ground. Of course that may not be a good ground. Any other options for ground in that area.

Also, what is PCB?

Bare metal “stuck” with a pointed meter lead is pretty good….if the voltage was low and you were comparing….maybe a better ground.

You have an UPSTREAM issue….as in….No POWER to the House Stud on the PCB (Printed Circuit Board) or the board in the picture,  

ONE FINAL TEST….start the engine.  Wait about 5 minutes.  Have your wife hold ON the Battery Boost Switch.  Then go to the PCB and check for Voltage to the right Stud or the terminal where that cable goes and the black cable is connected.  If you have 12 VDC or maybe closer to 13 or higher….Your House  Bank is dead or discharged.  The  Boost solenoid, SHOULD NOT HAVE BEEN DISCONNECTED as removing the House Bank.  Assuming That was left intact, the boost solenoid  will connect them….and the alternator is putting out 13.5 or so volts.  If STILL no power…..then read on….

with the engine running, put an automotive jumper cable between the chassis (starting) and House (Lithium).  Then you should have power.  If that works, you lithium has isses….no matter WHAT the inverter says.  No joy….you have to read on….

I saw the better picture.  The stud on the LEFT (solenoid) says House Switched….as in CONTROLLED by the Salesman Solenoid,  Trace the cable from the stud on the Right…..House NOT SWITCHED.  The cable coming in, I assume without your prints, is what is bringing power INTO or TO the PCB….and it has to come from the rear.  You need to start with the House Batteries.  If, as I suspect, you have a House Disconnect Battery Switch….then trace the positive from your House Bank.  Use any shiny metal ground….like you did up front.  The main house positive goes to the switch….then to a Buss.  There will be fuses…big ones.  One is the cable that goes up front….somewhere you have a loose or bad connection 

[saflyer]

2 hours ago, Tom Cherry said:

Bare metal “stuck” with a pointed meter lead is pretty good….if the voltage was low and you were comparing….maybe a better ground.

You have an UPSTREAM issue….as in….No POWER to the House Stud on the PCB (Printed Circuit Board) or the board in the picture,  

ONE FINAL TEST….start the engine.  Wait about 5 minutes.  Have your wife hold ON the Battery Boost Switch.  Then go to the PCB and check for Voltage to the right Stud or the terminal where that cable goes and the black cable is connected.  If you have 12 VDC or maybe closer to 13 or higher….Your House  Bank is dead or discharged.  The  Boost solenoid, SHOULD NOT HAVE BEEN DISCONNECTED as removing the House Bank.  Assuming That was left intact, the boost solenoid  will connect them….and the alternator is putting out 13.5 or so volts.  If STILL no power…..then read on….

with the engine running, put an automotive jumper cable between the chassis (starting) and House (Lithium).  Then you should have power.  If that works, you lithium has isses….no matter WHAT the inverter says.  No joy….you have to read on….

I saw the better picture.  The stud on the LEFT (solenoid) says House Switched….as in CONTROLLED by the Salesman Solenoid,  Trace the cable from the stud on the Right…..House NOT SWITCHED.  The cable coming in, I assume without your prints, is what is bringing power INTO or TO the PCB….and it has to come from the rear.  You need to start with the House Batteries.  If, as I suspect, you have a House Disconnect Battery Switch….then trace the positive from your House Bank.  Use any shiny metal ground….like you did up front.  The main house positive goes to the switch….then to a Buss.  There will be fuses…big ones.  One is the cable that goes up front….somewhere you have a loose or bad connection 

I did not have voltage to any of the posts on the salesman solenoid, large or small. Here is an image of the battery bay. BTW, that is where the boost solenoid is. Testing from the positive of the house batteries, red arrow, to the negative junction, yellow arrow, gives 13.4v. So the disconnect switch and batteries are good. From that junction it looks like the negative cable goes in the back wall and comes out I know not where.

Also, the battery boost switch is disconnected. I could use jumper cables between the house snd chasdis batteries fir your test.

5 hours ago, Dr4Film said:

Not sure but most coaches have it in the Rear Run Bay.

I am not familiar with the layout of your 05 Ambassador.

Posting a photo of your RRB would help.

Is the rear run bay the battery bay?

Edited February 20, 2023 by saflyer

[saflyer]

54 minutes ago, saflyer said:

I did not have voltage to any of the posts on the salesman solenoid, large or small. Here is an image of the battery bay. BTW, that is where the boost solenoid is. Testing from the positive of the house batteries, red arrow, to the negative junction, yellow arrow, gives 13.4v. So the disconnect switch and batteries are go. From that junction it looks like the negative cable goes in the back wall and comes out I know not where.

Also, the battery boost switch is disconnected. I could use jumper cables between the house snd chasdis batteries fir your test.

Is the rear run bay the battery bay?

What are the chances my 12v problems have anything to do with my leveling jacks not extending. I just tried the jacks and what I could hear above the low bag pressure warning was a click around the dash area.

[saflyer]

2 hours ago, saflyer said:

I did not have voltage to any of the posts on the salesman solenoid, large or small. Here is an image of the battery bay. BTW, that is where the boost solenoid is. Testing from the positive of the house batteries, red arrow, to the negative junction, yellow arrow, gives 13.4v. So the disconnect switch and batteries are good. From that junction it looks like the negative cable goes in the back wall and comes out I know not where.

Also, the battery boost switch is disconnected. I could use jumper cables between the house snd chasdis batteries fir your test.

Is the rear run bay the battery bay?

So, where do the positive and negative cables go from the battery bay to the front run bay? Does the positive one run uninterrupted there. I know where it comes in to the front run bay. What about the negative cable? Does it run uninterrupted. I know TC said there are some big fuses somewhere along one of the lines but where? I can’t identify it at the FRB OCB.

Edited February 20, 2023 by saflyer

[saflyer]

Ok, problem solved. Had a mobile RV tech come and in ten minutes found the problem. It was a resettable fuse or CB just downstream from the battery cutoff switch. Image attached.
 

Thanks for everybody’s advice. I will bypass the salesman switch soon, add a DCDC charge connection for the lithiums and possibly an Amp-L-Start to keep the chassis batteries charged.
 

One more question at the risk of thread drift. One thing I learned is my leveling leg activating switches are sticking. I need to take it out of the console and clean it. What kind of spray lube should I use?

Thanks again,       
Ed

 

 

[Tom Cherry]

1 hour ago, saflyer said:

Ok, problem solved. Had a mobile RV tech come and in ten minutes found the problem. It was a resettable fuse or CB just downstream from the battery cutoff switch. Image attached.
 

Thanks for everybody’s advice. I will bypass the salesman switch soon, add a DCDC charge connection for the lithiums and possibly an Amp-L-Start to keep the chassis batteries charged.
 

One more question at the risk of thread drift. One thing I learned is my leveling leg activating switches are sticking. I need to take it out of the console and clean it. What kind of spray lube should I use?

Thanks again,       
Ed

 

 

As I said, prints are your friend.  Remember I said look for a 80 or 100 Amp fuse.  The resettable Circuit Breaker is another way to provide protection and you don’t need a spare fuse.  That is on your prints.  If you followed the testing, that jumpering the batteries or the boost switch would not have solved the issue…..so then it had to be a switch (house disconnect) or a circuit protector (Fuse or circuit breaker).  This one is a resettable due to the high current….Monaco used high current fuses as well.  

As to your future plans, there are MUCH better ways to keep the Chassis Batteries charged.  The Amp L Start, I think, is out of business.  I am not a fan of them.  They actually are a “current thief” in that they steal from the house and bleed off to the Chassis.  I would be very cautious.  If you put one on and it keeps stealing voltage, you run the risk of damaging your expensive Lithium batteries.  Many folks use a digital battery tender that runs off AC.  You need one that is rated to put out around 1.75 - 2 amps.  Get one with the three phase (Bulk, Absorb and Float) cycles,  That is how your inverter works.  Most also have a “desulfonator” pulse that keeps your chassis batteries healthier,  plug it into shore….or if you don’t have shore power at storage, plug into your inverter and let the lithiums feed it.  I assume you have researched and have set the inverter so it does NOT keep inverting like a wet cell would do.  I can’t remember where I read the caution about having the Low Battery Cut off let fairly high, otherwise you deplete them and damage them. Many have Lithium here so if you use the search box and put in Lithium and choose “topics” you get a LOT good info.  Many have abandoned the charging section of their inverters and have AC powered supplemental charging to keep from toasting the Lithiums…..