Replacement New Alternator Problems - 06 diplomat - Including follow (8-10-23) discussion

[trstaska]

Two weeks ago, as we were leaving Massachusetts, our alternator froze up on the Mass Turnpike and wiped out the fan belt. By the time we found a safe place to pull over, we overheated and of course it was on a Sunday. We were towed to Bay State Truck Center in Springfield by CJ's towing. Monday morning Bay State got right to it and we were on the road by 1:00PM with a new alternator, fan belt and universal joint all for a thousand bucks which I thought was excellent. If you ever break down in that area, both companies are excellent.

All went well for two days, then in Port Huron, as we were leaving an RV park, the ALT/CHARGE light and alarm came on intermittently for a couple of seconds at a time. then I shut the engine off and fired up again and everything was fine until we were arriving in Minnesota three days later. Then, as we were approaching our destination, Dakota Meadows RV Park, Prior Lake MN., the ALT/CHARGE started acting up again! Intermittently, just a second or two at a time no pattern to it. I have a Silverleaf  system on the Dash and there is no increase or decrease in the voltage (steady at 13.8 13.9 once in a while as high as 14.1). I checked to make certain the belt is tight and i checked to make certain the wires on the alternator are tight and no loss of power. ANY THOUGHTS?

                                                                                                 TR Staska 06 Diplomat

[TomV48]

I had a very similar disaster befall me at the Reagan library on a Sunday.  I was only in a Ford explorer and I forget how but I found my way to a recommended shop after the auto club guy came put a little charge on the battery with his truck and jump started me.

Truck driver recommended was in fact open and seem to do right by me.   Cant complain on a Sunday.  The next day on my way home I got an intermittent alternator light.  I think I had that darn flashing light  for a year or two until that alternator failed.   Best explanation anybody could give me was crappy rebuilt alternator.

 

[trstaska]

By the way, can anyone give me a part# for a replacement alternator for an 06 Dip. ISL 400  160 amps. I might want to buy a spare alternator!

                                        TR Staska 06 Dip

[jacwjames]

Monaco usually installed a Leece Neville Duvac alternator.  Do you know if the alternators that were installed Duvac type alternators. 

You can install a none Duvac alternator with a change in which wires you connect, I believe the Duvac use a sense wire that can be left disconnected. 

 

In 2014 when my Leece Neville alternator failed I just had it rebuilt and it's been running ever since.

[Jdw12345]

I live about 45 minutes from the resort you’re currently at, I trucked for my self for many years, these are the people that did all of my alterations and starter rebuilds, I always had good experiences with them, they are on the northern side of the cities but at least you have a reputable resource, at least they did right by me.

 

https://www.grayautoelectric.com

 

Edited July 8, 2023 by Jdw12345

[waterskier_1]

According to my 2006 Diplomat Wiring Diagram, you do indeed have a DUVAC Alternator.  This type of alternator is used to sense the voltage somewhere other than the output of the alternator.  That "somewhere" may be on the battery side of an isolator where there is a voltage drop between the alternator input and the battery itself (typical of a Solid State Isolator with Diodes).  That somewhere may also be at the end of a longer run of cable, which could have a voltage drop due to the distance and current.  You do not have a Solid State Isolator, but instead have an IRD (Isolator Relay Delay).  

In any case, the Sense wire of the DUVAC MUST be connected, or the alternator will assume there are zero volts (an open) and attempt to run at max output, eventually overheating and possibly burning itself up.  

I wonder if the correct alternator was installed, or if it the alternator was installed correctly.  I say this because you should have 14.2 - 14.4 volts at the chassis battery when the alternator is running.  You state you only have 13.8 - 13.9.  The ALT-FAIL relay is a 6 volt relay (likely the only 6-volt relay in the coach) which gets its input from one of the three windings on the alternator.  If the alternator output drops, so does the voltage on the winding, causing the ALT-FAIL relay to drop out and the ALT-FAIL light to come on.  

One other thing that can cause the ALT-FAIL light to come on is to have another charging source connected to the chassis battery.  This is usually the battery charger when running the generator.  But your coach doesn't automatically charge the chassis battery from the inverter/charger.  Also, solar charging can cause this, if the solar is connected to the chassis battery.

You really need to know the voltage AT THE CHASSIS BATTERY when the ALT-FAIL light comes on to determine if it is the alternator, wiring of the alternator, or other circuitry causing the light to come on.

  -Rick N.

[Scotty Hutto]

Here is the alternator info for a 2006 Dip. 
 

The unit shown below is a direct replacement, per the Presto-Lite (Leece-Neville) website. The 110-912 has been discontinued. 

 

Hope that helps!

[Tom Cherry]

15 hours ago, trstaska said:

Two weeks ago, as we were leaving Massachusetts, our alternator froze up on the Mass Turnpike and wiped out the fan belt. By the time we found a safe place to pull over, we overheated and of course it was on a Sunday. We were towed to Bay State Truck Center in Springfield by CJ's towing. Monday morning Bay State got right to it and we were on the road by 1:00PM with a new alternator, fan belt and universal joint all for a thousand bucks which I thought was excellent. If you ever break down in that area, both companies are excellent.

All went well for two days, then in Port Huron, as we were leaving an RV park, the ALT/CHARGE light and alarm came on intermittently for a couple of seconds at a time. then I shut the engine off and fired up again and everything was fine until we were arriving in Minnesota three days later. Then, as we were approaching our destination, Dakota Meadows RV Park, Prior Lake MN., the ALT/CHARGE started acting up again! Intermittently, just a second or two at a time no pattern to it. I have a Silverleaf  system on the Dash and there is no increase or decrease in the voltage (steady at 13.8 13.9 once in a while as high as 14.1). I checked to make certain the belt is tight and i checked to make certain the wires on the alternator are tight and no loss of power. ANY THOUGHTS?

                                                                                                 TR Staska 06 Diplomat

@trstaska

please read this thread

@vanwill52 Wrote or started the most authoritative as well as a common sense explanation.  Most likely the shop did not realize that the “this will work” alternator will or might not.  You or someone with electrical savvy will need to get the model number of the new unit.  Then pull the PDF on it and review how the voltage regulator is configured or the type.  Then do the same for the original Leece Neville and then read Van’s thread and determine if or how the MH needs to be wired or connected.

Unfortunately, very few of even the top rated truck and bus electrical shops don't  stop and read but just trust the “cross reference” charts.  Your situation has been played out here dozens or more times since I joined some 14 years ago and I have read almost every post since then and was made a moderator some 12 years ago.  Don’t feel bad.  Just read and do your homework and it is possible to salvage and make it work.

There are no shortcuts.  You have to know exactly what was installed and which wires in the Alternator harness are connected to which terminal.  

There was also an “upgrade or revision” in the “alt fail” circuit.  I don’t know the specifics but @Frank McElroy has commented on it.  He may or may not chime in as he has been engrossed in a special project and has only been doing cursory “following”.  If he doesn’t, PM him.

We have a lot of folks with experience here in addition to Frank and Van as to a Leece Neville conversion.  I would keep my Silverleaf on at all times and monitor it like a hawk, but not impacting my “driving”.  I would have a pair of Jumper cables if the Chassis battery seems to crank slower.  Manually Jumpering the House and Chassis for a cranking assist works.  Some have driven with this when their alternator was flaky by running the generator and keeping voltage or charging voltage on the Chassis system.

Here is my “shade tree” load test.  If you drive on a day where the temps are in the mid to upper 90’s…maybe lower 90’s. Find a stop.  Leave the dash AC on max.  After a few hours, the engine and transmission will be about as hot and totally heat soaked and the area around them is hot.  Turn off the engine.  Wait about 10 minutes or so….in my case, the time to unhook the toad, stow and put the cover on the tow bar, etc.  Then start the engine….if the generator is running for the House AC, have it turned off so all is quiet in the cabin.  If you get that OMG “IT AIN’T TURNING OVER” pause, but then it fires up, YES….the cranking batteries are getting a little weak and you need to replace in a few months.  But it starts normally and you didn’t have a brief panic attack….you’re fine.  When the engine is shut down and does a heat soak after the coolant stops circulating, this is the time the starter and battery pull max current.  

Hope this helps

 

 

[MyronTruex]

Were you running the generator when you got the alt fail light warning???

This is perfectly fine but just want to know. The onboard charger can confuse the alternator warning light system when the batteries are basically fully charged and the voltages are at their peak. 

Often turning on headlights or the dash air conditioner can provide enough of a load to make things happy. 

Your old alternator may never have put out quite enough voltage to cause the conflict. 

This is a common issue on some models that use the battery combining solenoid system. It can happen especially when on shoreline and with the engine running. 

On some models there is a generator sense line that keeps the battery banks isolated from each other so the issue does not come up. But that isolation does not happen on shoreline.

I am talking in very general terms here since I do not know your exact setup nor do I know what possible modificatons someone has made. Just saying your issue may NOT be a real problem.

[Scotty Hutto]

I guess the first question we should ask is what did Bay State Truck Center install?  Leece-Neville, Delco 28SI, or something else?

It’s critical to know whether they put a L-N DUVAC alternator or something else before heading down the troubleshooting path.  The troubleshooting paths diverge depending on what they installed.  

Having an Alt Chg light may indicate a problem, or not, depending on what was installed, as Myron notes above. 

My 2006 Dip charging system is completely OEM (at the moment), and I can do things in a certain order that will cause it to come on. And sometimes, it just wants to remind me it’s there…🤷🏻‍♂️ I can drive 2 hours with the genny running with no issue, and suddenly it pops on. Having fully tested it, I can say with confidence that my Trombetta relay, my IRD, and my alternator are functioning properly. 

[trstaska]

The alternator Bay State installed is a Wilson 90-01-4577N, 160amp alternator. One of the things that I thought of is that I have a Trik-L-Start charger charging my chassis batteries from the house batteries that I leave connected all of the time. It's never been a problem in the past but maybe the new alternator doesn't like it? I checked the diagnostics in my Silverleaf and no voltage abnormalities showed up. I have a plug in voltage readout on the console that tells me that the Trombetta, the IRD and the inverter are working when we are going down the road. What do you think?

[trstaska]

The Alternator is a Wilson #90-01-4577N. I put more info on posts to Hutto and Truex so I won't repeat it here. Any suggestions are appreciated. Also, I do notice that I am getting that scary pause sometimes when starting up. The chassis batteries are 5 years old. I disconnected the Trik-L-Start the other day and left it off for two days then checked the voltage. The voltage was 12.4 on the chassis batteries. I'm getting a new hip this Thursday so my crawling around under the coach is kind of limited for the next 4-6 weeks.

[trstaska]

I was not running the generator when this happens. The Alternator is a Wilson #90-01-4577N. I put more info on posts to Hutto and Truex so I won't repeat it here. Any suggestions are appreciated. Also, I do notice that I am getting that scary pause sometimes when starting up. The chassis batteries are 5 years old. I disconnected the Trik-L-Start the other day and left it off for two days then checked the voltage. The voltage was 12.4 on the chassis batteries. I'm getting a new hip this Thursday so my crawling around under the coach is kind of limited for the next 4-6 weeks.

[Tom Cherry]

11 minutes ago, trstaska said:

The Alternator is a Wilson #90-01-4577N. I put more info on posts to Hutto and Truex so I won't repeat it here. Any suggestions are appreciated. Also, I do notice that I am getting that scary pause sometimes when starting up. The chassis batteries are 5 years old. I disconnected the Trik-L-Start the other day and left it off for two days then checked the voltage. The voltage was 12.4 on the chassis batteries. I'm getting a new hip this Thursday so my crawling around under the coach is kind of limited for the next 4-6 weeks.

Lots of info.  If you are monitoring  and recognize the warnings then, have the handy “universal fix” jumper cable ready and drive on.  The ALT FAIL false reading or occurrence is something I know of, but not an expert.  PM @Frank McElroy for info.  I know he has posted as well as described it to me….

I WOULD drive for a few hours.  Then maybe right after you stop.  Flick on the headlights for a few second or less than 10 seconds.  Then quickly turn off the chassis battery (disconnect switch) pull the Negative.  Pull the negative jumper (assuming 2 chassis battery).  Then, use your DVOM & measure the voltage.  The 12 V column is your standard…..whether house or chassis.  Doing the correct method and measuring then gives you the correct SOC.   12.4 Is probably 75% based on how Trojan told me to interpolate.

Good luck with Hip.  Hope you are getting the ROBOT assisted (MAKO) surgery.  That works for one kind only.  Back or front….don’t remember…but we have had two joints….shoulder (not now done robotically) and knee (robot).  I was my wife’s personal trainer/therapist for her knee.  She had better range of motion and strength after almost 6 months of that BEFORE the replacement than in the past 3 years.  She has set new records for PT Recovery and 5 PT folks have said she is way more advanced as in recovery than any 77 YO they have ever seen.  Her SIL, 10 years younger was almost an invalid had the robotic hip replacement. The robotic hip worked wonders.  Her older sister had had  two done conventionally and is her care provider and can’t believe how much quicker she is recovering…

Good Luck.  I’m on my 15th week of shoulder but did a lot of PREHAB and have done my PT religiously and have the record, given to me by  an Ex Olympic PT person who has 30 years of experience.  She raves at my progress….

[waterskier_1]

4 hours ago, trstaska said:

The alternator Bay State installed is a Wilson 90-01-4577N, 160amp alternator. One of the things that I thought of is that I have a Trik-L-Start charger charging my chassis batteries from the house batteries that I leave connected all of the time. It's never been a problem in the past but maybe the new alternator doesn't like it? I checked the diagnostics in my Silverleaf and no voltage abnormalities showed up. I have a plug in voltage readout on the console that tells me that the Trombetta, the IRD and the inverter are working when we are going down the road. What do you think?

You could disconnect this to see if that is causing the problem.  If it is, and it didn't before, then maybe it (the Trik-L-Start) isn't the problem, but the alternator might be.

  _Rick N.

3 hours ago, trstaska said:

I was not running the generator when this happens. The Alternator is a Wilson #90-01-4577N. I put more info on posts to Hutto and Truex so I won't repeat it here. Any suggestions are appreciated. Also, I do notice that I am getting that scary pause sometimes when starting up. The chassis batteries are 5 years old. I disconnected the Trik-L-Start the other day and left it off for two days then checked the voltage. The voltage was 12.4 on the chassis batteries. I'm getting a new hip this Thursday so my crawling around under the coach is kind of limited for the next 4-6 weeks.

12.4 Volts is below 50% charge.  You should have 12.7 for a fully charged battery.  

I don't know what your plug in monitor for Trombetta, the IRD and the inverter are working is connected to, but when you are troubleshooting (versus just Monitoring), you need to go to the source.  There can be unknown voltage drops over long wires between the front and the back of the coach.  You should have 14.2 - 14.4 Volts on the Chassis battery - Measured AT THE BATTERY, with a VOM.  If you don't have this voltage, then the alternator is not wired correctly, or is defective (or the wrong alternator).  Hopefully you can check this without crawling under the coach.  

  -Rick N.

 

[waterskier_1]

16 hours ago, Scotty Hutto said:

Here is the alternator info for a 2006 Dip. 
 

The unit shown below is a direct replacement, per the Presto-Lite (Leece-Neville) website. The 110-912 has been discontinued. 

 

Hope that helps!

The Plot Thickens!  My 06 Diplomat Wiring Diagrams clearly show a DUVAC alternator.  Upon closer inspection, I see that the specific drawing is dated 2002.  So, it seems there were changes made, that are not documented - surprise, surprise.  I went 2007 Wiring Diagrams, and the DUVAC is NOT used (Drawing dated 8/8/06).  But what really struck me is they are no longer using ALT-FAIL relays.  The updated alternator has a "lamp driver" output which connects directly to the ALT-FAIL lamp on the dash.  Since I don't have any details (it seems the Prestolite site has changed a lot since I last visited and they no longer have detail specifications listed).  I don't know what exactly the "lamp driver" is connected to inside the alternator.  The older versions had all three of the 3-phase stator windings on the back of the alternator, and that is what Monaco used to control the ALT-FAIL Relay.  As I mentioned before, that was a 6-volt relay.  I won't go into the theory of operation, since it seems moot in light of the design change.  I also don't know if or how having another charging source might affect the ALT-FAIL lamp.  

I stick by my suggestion that the voltage at the chassis battery measurement is going to reveal the real condition of the alternator and the charging circuit and voltage regulator.  Without being at the coach and taking actual voltage measurements of the "lamp driver" output under various conditions, I can't help further.  

  -Rick N.

[MyronTruex]

With your additional information, you have the classic conflict going on between two charging systems. 

Next time you get the alt fail light with the generator and engine running, turn the generator off and see if it goes away in a few seconds or a minute or so. If it goes out, start the generator again and when or if it comes on again, turn on your headlights to see if th extra load calms things down.

As a side note, if your engine batteries are five years old they have given you more life than most. Batteries are never really purchased, they are simply rented. They are critical to your systems and I won't go into how they can cause more problems than just about anything on these forums.

[trstaska]

9 minutes ago, myrontruex said:

With your additional information, you have the classic conflict going on between two charging systems. 

Next time you get the alt fail light with the generator and engine running, turn the generator off and see if it goes away in a few seconds or a minute or so. If it goes out, start the generator again and when or if it comes on again, turn on your headlights to see if th extra load calms things down.

As a side note, if your engine batteries are five years old they have given you more life than most. Batteries are never really purchased, they are simply rented. They are critical to your systems and I won't go into how they can cause more problems than just about anything on these forums.

It happens as I am traveling down the road and the generator is NOT running. I realize it can happen if the generator is running or if I am plugged in. That is not the problem. We are parked in an RV Park in Prior lake MN for  4-6 weeks while I get a new hip. Maybe tomorrow or Tuesday I'll disconnect the shore power and fire up and take a reading at the chassis batteries if I get the alarm. It's so inconsistent though, that I don' know if I will get the alarm.

thanks to everybody for the advise. TR Staska 06 Dip

And I hope I pressed the right button 

[jacwjames]

FWIW,

When I was getting ready to leave ~2.5 weeks ago and fired up the engine I got a Alt Fail light.  I do have a Bluesea installed and alternator was charging both banks.  The coach had been plugged in and the house batteries (~2 years old) and chassis battery (2 month old) were fully charged.  I had the Silverleaf on and it was showing slightly higher volts, reached down and pulled out the head light switch and the Alt Fail light went out. 

Drove ~750 miles without a problem and 200 miles the next day.  Life is good!

[Larry Laursen]

I had a similar experience with my 05 Endeavor. My Alt Fail light came on last summer. I removed the relay in the compartment below the driver's window for the rest of the trip. This was the second or third time doing this.  I had it at the shop that fixed it in the past this spring; however, they couldn't fix it. New techs and service writers. While driving this past month to MI the Park Brake light was also on.  I discovered that when I turned on the high beams the Park Brake light went out.  I had an appointment arranged at Speed Wench in Hudsonville MI. They found a short in the daylight running light (DRL) circuit that had blown 2 fuses. They removed the DRL relay and everything worked. Now I don't have DRL but don't need the.  I have tried to find the connection between the DRL and the Alt Fail circuits from the schematics but haven't been able to do it.

REGARDING "DUVAC"

Monaco used the DUVAC alternator when they installed the Cole-Hersee solid state dual battery charger (DBC) system.  Thus, the DUVAC connection on the alternator is not used on needed on coaches without the DBC. The alternator is self-energized on coaches below Imperial and Windsor before 2004 and everything after that.  YES, the schematic drawing for the non DUVAC coaches still show the DUVAC connected to the alternator. I have this drawing: 38041505 Chassis Wiring.dwg which is in the files section.

I recommend Speed Wrench if in west Michigan: Contact Speed Wrench Today | Heavy Duty Repairs | Body Shop

[waterskier_1]

2 hours ago, Larry Laursen said:

REGARDING "DUVAC"

Monaco used the DUVAC alternator when they installed the Cole-Hersee solid state dual battery charger (DBC) system.  Thus, the DUVAC connection on the alternator is not used on needed on coaches without the DBC. The alternator is self-energized on coaches below Imperial and Windsor before 2004 and everything after that.  YES, the schematic drawing for the non DUVAC coaches still show the DUVAC connected to the alternator. I have this drawing: 38041505 Chassis Wiring.dwg which is in the files section.

 

Larry, I couldn't find the specific drawing you are referencing.  I looked in the 2004 Windsor Wiring Diagram, but it still has Drawing # 38031242, which still shows a DUVAC alternator, although it's not being used with a SSI (Solid State Isolator).  

You are correct that the need for DUVAC is/was based on the Forward Voltage drop of the diodes used in the SSI, which would not allow a "normal" alternator to fully charge the batteries.  It is still used where there are long runs of battery cables where the potential for I**R voltage drop may be significant (voltage drop due to the resistance of wire at high current flow).  There is no problem using a DUVAC alternator, with the DUVAC terminal connected directly to the alternator output.  This all has to do with the reference for the Voltage Regulator.  I don't see any connection with self-energizing.  

As I previously mentioned, a drawing I found dated June of 2006 shows the replacement of the DUVAC alternator with an alternator that has a Lamp Driver output, which does away with the ALT-FAIL circuitry and ALT-FAIL Relay.  

  -Rick N.

[Scotty Hutto]

21 minutes ago, waterskier_1 said:

As I previously mentioned, a drawing I found dated June of 2006 shows the replacement of the DUVAC alternator with an alternator that has a Lamp Driver output, which does away with the ALT-FAIL circuitry and ALT-FAIL Relay.  

  -Rick N.

Rick,

I'm heading over to my coach today and will take pictures of my alternator.  If you still have the updated drawing please upload it (if you haven't already).  My electrical drawings still show the DUVAC alternator 🤦🏻‍♂️; I'd love to get a copy of the correct drawings... at least for the alternator!!

[waterskier_1]

16 minutes ago, Scotty Hutto said:

Rick,

I'm heading over to my coach today and will take pictures of my alternator.  If you still have the updated drawing please upload it (if you haven't already).  My electrical drawings still show the DUVAC alternator 🤦🏻‍♂️; I'd love to get a copy of the correct drawings... at least for the alternator!!

This is an updated drawing, but I can't say for sure it is what you have.  It does give a good pictorial view of the rear of the alternator though.

  _Rick N.

2007 Knight_Ambassador Alternator.pdf

[Larry Laursen]

The drawing I am referencing is a .dwg file. You will need to use a drawing viewer.  I use Autodesk DWG Trueview 2024 which is free to use.  The drawing shows the DUVAC connection but is not correct. This is my experience.

In 2017 I had the alternator replaced. They installed a Leece-Neville LH110-555PHO 165 Amp. The original was LBP2180.  I don’t know the difference.  Since the installation I have had off and on again problems with the Alt Fail light.  The shop fixed it and said a loose wire, as I recall.  Last summer the Alt Fail came on and I had to remove the relay to turn it off.  I have a Scanguage D so can keep track of the voltage.  I had the coach in the same shop for several months repairing the fan and radiator as the fan mount bearings froze and the fan came off putting a small hole in the radiator.  I asked them to fix the Alt Fail.  They came back that it couldn’t be repaired, and the inverter was causing the problem.  I disagree with them on that explanation, but decided not to press on at $160/hr.

The circuit, as I understand, uses a voltage signal from the alternator field that is 6 volts.  There is a 6 volt relay in the compartment below the drivers window on mine that is powered by this 6 volt signal and has a 6 volt coil.  The relay is in the ground side of the indicator light and a NC contact is used to take it to ground when the relay is not activated.  I have put a VOM across the relay coil feed and don’t get any voltage with the engine running.  Thus, the signal voltage is not coming to the relay.  I can’t find any good diagrams of the alternator that show what terminal is the field voltage connection for the 6 volt signal to help them.  The rear of the alternator is hard to get to on my rear radiator unit, so I haven’t been able to check it out.  The Alternator Fail attachment shows the circuit, but the 05 Endeavor doesn’t have the DUVAC set-up.  Most of the show the battery +/- terminals and then 3 terminals in an arc that are AC or tach.  I have seen a few with another “lamp” on the regulator housing.

This the page for the OEM alternator PRESTOLITE LEECE NEVILLE LBP 12V 160A BRUSH ALTERNATOR-LBP2180GH (peivinlookup.com)

This is the page for the current alternator: PRESTOLITE LEECE NEVILLE 8LHP 12V 160A BRUSH ALTERNATOR-8LHP2170VF (peivinlookup.com)

I don't have a solution 

38041505 Chassis Wiring.dwg

[Scotty Hutto]

Larry, Rick,

Here is the Chassis Wiring file converted to PDF.  I used large format so you can zoom in close...

38041505 Chassis Wiring.pdf

Also, I went by the coach and confirmed my 2006 Dip does indeed have a L-N 110-192 (AKA LBP2180).  It is wired as per the diagram Rick provided above (which I added to our files).