Billhump Posted April 20, 2021 Share Posted April 20, 2021 We have a 2006 Diplomat - 400 ISL Cummins engine with an original LEECE NEVILLE #LBP 2180 160 Amp alternator. The original alternator was just replaced with a new LEECE NEVILLE # LNLB 2180 GH at a Cummins repair center. Now the ALT/Charge fail light will not go off. I told the Cummins Service manager that this light was controlled by the 6V terminal on the back of the alternator which goes to a 6V relay in the front bay under the driver's seat. After being at the Cummins Repair Center for more than a month, I have now picked up the coach and will troubleshoot the problem myself. I have talked to a Leece Neville service tech and was informed that all 3 terminals on the back of the alternator have 7.5V. I have tested the 6V relay socket for this circuit and have no power at terminal 86 with the engine on, and terminal 85 is the ground. This was confirmed by both a multi meter and the labels on the wires to the socket. The alternator is producing a 13.7V charge to the batteries. The horn, lights, wipers, and dash instruments all work. My first question would be: Is there a fuse between the alternator terminal and the 86 port on the relay socket? 2. Do all 3 terminal in the back of the alternator produce 7.5V? HELP!! Link to comment Share on other sites More sharing options...
David Schmees Posted April 20, 2021 Share Posted April 20, 2021 As far as I have seen on mine, the center terminal is +- 6 v. There is a 5 Amp fuse on a pigtail on the back of the alternator along with other wires there. Link to comment Share on other sites More sharing options...
vito.a Posted April 20, 2021 Share Posted April 20, 2021 Just wanted to say the alternator fault light will normally come on if you are plugged into shore power or the generator is running. Hope you get it sorted out! Link to comment Share on other sites More sharing options...
waterskier_1 Posted April 20, 2021 Share Posted April 20, 2021 If you have no voltage on pin 85 (pin 86 and pin 30 go to ground) then I would check the inline 5 Amp fuse. Are you checking AC or DC voltage at pin 85? You can check the relay by simply removing it....and the ALT FAIL Light should go out. It is not clear which "all 3 terminals" of the total of 8 or 9 terminals you are referring to. There are two large terminals, which are ground and +12VDC main output. There are 3 field (stator) connectors. Then there is the Ignition Terminal and the DUVAC Terminal. I'm hoping that the alternator is wired correctly. Maybe you could confirm which wires are on which terminals. I have helped dozens when replacing their alternator, and over 90% of the problems were incorrect wiring. Are you sure you got the correct Alternator? I don't show the 2100 Series as DUVAC Alternators. Link to comment Share on other sites More sharing options...
Billhump Posted April 21, 2021 Author Share Posted April 21, 2021 Thank you Rick N. The alternator installed on the coach at the factory was a Leece Neville #LBP 2180, Cummins service center replaced that alternator with a Leece Neville #LNLB 2180 GH. When I called Leece Neville today, they told me that the two alternators were the same. I believe this alternator has 3 field (stator) connections, the two large terminals which are ground and a 12 VDC main. There are no terminals for ignition or DUVAC terminal. Tomorrow I will check the wiring that I have and look for the 5 AMP fuse. Thanks again Link to comment Share on other sites More sharing options...
waterskier_1 Posted April 21, 2021 Share Posted April 21, 2021 I'm only going by the 2006 Diplomat Wiring Drawings. I have no personal experience with that alternator. 2006 Diplomat wiring diagrams Alternator.pdf Link to comment Share on other sites More sharing options...
waterskier_1 Posted April 21, 2021 Share Posted April 21, 2021 19 hours ago, Billhump said: The alternator is producing a 13.7V charge to the batteries. I just though about this last night. The output should be regulated at 14.1-14.4 volts. Your 13.7 is low - more like a float voltage from a smart charger, which the alternator is not. This could be due to the DUVAC terminal not being connected correctly. Or it could be you have other battery related problems. Lastly, it could be the alternator is defective, not putting out the full charge voltage, which would also trigger the ALT FAIL circuit. I suggest you re-check the wiring of the alternator, specifically the DUVAC terminal (if there is one - as per the drawing) and troubleshoot the low alternator output first. Once that is corrected, you may also correct the ALT-FAIL indicator. Link to comment Share on other sites More sharing options...
waterskier_1 Posted April 21, 2021 Share Posted April 21, 2021 Update: I just pulled the Prestolite data sheet for the alternator number you provided. It does NOT have DUVAC (as the drawing for 2006 Diplomat shows it). Given that, and since I have no drawing to determine how it was originally wired, I'll provide some educated thoughts. First, since there is no DUVAC or any other means for external input of battery condition, and the regulator is internal (built into the alternator) I conclude that the voltage sensing is based on the main 12 Volt battery voltage. There is no ability to compensate for voltage drop between the alternator and the battery. This is only a real problem when there is some sort of Isolator used between the alternator output and the actual batteries. Again, based upon the 2006 Diplomat Wiring Diagrams I have, you don't have an Isolator (solid state device) but rather some implementation of a Big Boy Relay. That said, I recommend that you check the output at the alternator, not at the battery (yes they SHOULD be the same) and confirm it is not at the Prestolite Specification of 14.2 (14.1-14.4) volts. If the output of the alternator is not at the correct voltage, check you batteries and cables, though this is unlikely the cause. More likely the voltage regulator in the alternator is defective, or possibly some other internal (diode) is bad. In any case, I suspect, if your reading are correct, that you have a defective alternator. Before troubleshooting a bad ALT-FAIL signal, first make sure the alternator is good....it may be telling you that indeed your alternator is defective. Link to comment Share on other sites More sharing options...
Billhump Posted April 21, 2021 Author Share Posted April 21, 2021 Rick, when Cummins checked this alternator, they indicate on the bill that they had 13.8 VDC on the battery studs of the chassis batteries. The chassis batteries are isolated from the house batteries with an isolation relay located in the main fuse box under the driver’s seat. The 2 chassis batteries are new and maybe 3 months old. I will check the VDC at the alternator this afternoon. I am presently going through the electrical system and have found the auxiliary lights, docking lights and mirror adjustments are not working now, but worked before alternator change out. My led daytime running lights are now pulsating when the engine is running. Thanks for your troubleshooting knowledge. It’s very helpful. Link to comment Share on other sites More sharing options...
waterskier_1 Posted April 21, 2021 Share Posted April 21, 2021 32 minutes ago, Billhump said: Rick, when Cummins checked this alternator, they indicate on the bill that they had 13.8 VDC on the battery studs of the chassis batteries. The chassis batteries are isolated from the house batteries with an isolation relay located in the main fuse box under the driver’s seat. The 2 chassis batteries are new and maybe 3 months old. I will check the VDC at the alternator this afternoon. I am presently going through the electrical system and have found the auxiliary lights, docking lights and mirror adjustments are not working now, but worked before alternator change out. My led daytime running lights are now pulsating when the engine is running. Thanks for your troubleshooting knowledge. It’s very helpful. I would start at the alternator. That is where/when the problem occurred. I think that the 13.8 VDC is low - maybe low enough to cause problems. I agree that since you have the isolation relay, and hopefully short (less than 5-ft or so) battery cables, that the DUVAC system is not needed....I'm surprised that is what the drawings call out. What else happend/was touched when the alternator was replaced. It's quite odd that several systems are not working if that is all that was done. 1 Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted April 21, 2021 Share Posted April 21, 2021 I would have guessed it was a Duvac system and then the 06 Diplomat drawings show Duvac. Perhaps the replaced alternator was not the proper one, unless the OP knows for sure. It could have been replaced before with the wrong one This is why this forum has recommended for a along time to get the alternator rebuilt. The complications that can follow replacing it can be hard to rectify. Especially after the old alternator is gone. Link to comment Share on other sites More sharing options...
Billhump Posted April 22, 2021 Author Share Posted April 22, 2021 Problem Solved- This 2006 Diplomat has a LEECE Neville alternator, which is different from the DUVAC alternator used in the Monaco models above the Diplomat. After some research and help from this forum, I began checking the Electrical Systems in the coach: Here is what I found. Alternator VDC output at the positive and negative terminals (engine running) 14.15 DC, the 3 auxiliary field (stator) terminals output 7.2 VCD each. When I rewire the alternator per 2006 Monaco diplomat wiring diagram, the alt/charge fail light and annunciator now work as they should. Special thanks to WATERSKIER-1 and all who provided help to me on this problem. 2 Link to comment Share on other sites More sharing options...
waterskier_1 Posted October 24, 2022 Share Posted October 24, 2022 I can't answer for you coach, I've not worked on the year. On the older coaches made by the original Monaco, the alternators had 3 smaller wires in addition to the main large positive & negative cables. One was for the ignition, one for the DUVAC input, and the last was the Alternator Fail wire. It was connected, through a fuse, to a ALT-FAIL Relay located in the Front Run Bay. This was a special 6-volt relay and it drove the ALT-FAIL light on the dash. If Yuku pulled the Relay, the alarm would go away, but you'd also inhibit any valid alternator deterioration warnings. Link to comment Share on other sites More sharing options...
Happycarz Posted October 24, 2022 Share Posted October 24, 2022 For many years Monaco used this wiring setup for the alternator in the attached picture. This one pertains to the 2008 & 2009 Camelot, Scepter, and Contessa coaches. It shows the front and rear run panels in green and shows the connection to such. Other years and models tied in the ignition and remote sense similarly but in different places. Hope this helps. Tom, make a copy for your records. This is specifically how yours is set up. Link to comment Share on other sites More sharing options...
Tom Cherry Posted October 24, 2022 Share Posted October 24, 2022 13 hours ago, Monacotom said: I appreciate your response and the schematic. Monaco must have had different configurations in later models because I do not have all those connection wires. The 4327N Wilson/ Delco 200 amp alternator must have been installed incorrectly by the roadside tech. The big red wire on +, and both the white and black wire on the - terminal. The alternator still charged but I had a fault at the dash. My problem is determing the correct terminal post for the white wire so the fault light on the dash goes out. There are two smaller post remaining on the back of the alternator. Might be overkill but someone other myself could benefit from the info. Happily the bedroom floor is open and it's just a latter of one wire connection, I hope. You are correct....or at least I think so. When Navistar started to use their engines, God only KNOWS who had input and switched to the Wilson/Delco. ON ALL the Cummins, it was, as best I can determine, the Leece Neville. Now understand....Cummins engines were used up when Navistar bought Monaco. For EXAMPLE.... and this is documented....I personally know this....and did some research. The Camelot's in 2009 were a Cummins ISL with the Cummins VGT Turbo (exhaust) Brake. THAT WAS IT. Now the Dynasty, dating back to 2008, used the SAME engine. BUT, it was a special Cummins build (or Monaco bought it that way) with the 2 stage (OFF, LOW & HIGH) Jacobs (JAKE) Brake that is part of the valve and head assembly. It was NOT an engine that Monaco would put, even for special folks.....maybe, into the Camelot/Scepter Line. BUT....along came the hard times. Bankruptcy was eminent. SO, Cummins MIGHT not have extended credit? Monaco figured out that building higher end Dynasties was NOT gonna help their bottom line. They were fighting for SURVIVAL. OK....the Production Control Geeks started scheduling MORE Camelots and Scepters. OPPS. NO ENGINE. SO, they tapped into their over inventory of Dynasty Engines. Some later 2009's that got trapped and eventually left as 2010 (under Navistar) got the Dynasty Engine for a $2,900 add ON. THEN.....Low and BEHOLD.....Navistar got the bright idea. WHY NOT use up these crappy engines. We KNOW our MaxForce is better and we will totally eliminate Cummins. SO, in 2010, the Camelot and Scepter had an OPTIONAL.....easy to order.....EXHAUST BRAKE....which was actually the Jake Brake. The sales brochure has this. FIRST TIME A JAKE WAS AN OPTION on that model(s). Fast FORWARD to 2011. OPPS....we GOT MORE of them Dynasty Engines so it is NOW STANDARD. YES....the Sales Brochure NOW TOUTS THAT..... The owner's manuals for the 2009, 2010 and 2011 actually document this. The OPTIONAL OFF/LOW/HIGH Exhaust brake (straight from the Dynasty Manual) is NOW in the 2010 manual. THEN, the 2011 has it as STANDARD....same copy as the Dynasty. Alas and alack.....there was NO 2012 Camelot....Maybe demand....,maybe they ran out of engines. WHO KNOWS. BUT, you have the Navistar Max Force Engine and it is (could be....surely is) different as to the Alternator and how it works. THAT is the reason that we ask folks to put their info down like you did. It takes a WHOLE LOT OF DETECTIVE WORK to figure these things out....and sometimes we assume that THINGS are the same. The old tongue in cheek saying is closer to the truth that we like. Monaco NEVER made two MH's alike....even the same model ont he same day....right behind the other. Thanks for the info. 1 Link to comment Share on other sites More sharing options...
dandick66 Posted October 27, 2022 Share Posted October 27, 2022 I have the Leece-Neville 3700150C92, 160 amp alternator in my 2012 Diplomat with the Maxxforce 10. As far as accessing the alternator, it’s difficult to get to from the top or the air filter housing area. You can see it, but not reach it easily. I have not removed mine, just was looking at in case I had to change it sometime. I also found a couple of pictures of the Leece Neville and it looks like the white wire is grounded and red is positive. You said the original 160 amp alternator was replaced. Was it the Leece Neville? Also, the International dealer was right about not using the International body control. As far as I can tell, Monaco used Medallion. Good luck trying to find out much about how it interfaces. I contacted Medallion several times before I was actually able to speak to someone. The guy I talked to said the guy that did the Monaco stuff didn’t work there anymore so they didn’t have any information. How did you unplug the annunciator? If I recall, mine is surface mounted to the circuit board and I didn’t see any way to unplug it. I did put some electrical tape over it so it wasn’t so loud. I see you’re in Yorktown. I’m across the river in Gloucester. Link to comment Share on other sites More sharing options...
96 EVO Posted January 5 Share Posted January 5 On 10/23/2022 at 7:49 PM, waterskier_1 said: I can't answer for you coach, I've not worked on the year. On the older coaches made by the original Monaco, the alternators had 3 smaller wires in addition to the main large positive & negative cables. One was for the ignition, one for the DUVAC input, and the last was the Alternator Fail wire. It was connected, through a fuse, to a ALT-FAIL Relay located in the Front Run Bay. This was a special 6-volt relay and it drove the ALT-FAIL light on the dash. If Yuku pulled the Relay, the alarm would go away, but you'd also inhibit any valid alternator deterioration warnings. Rick, if I'm reading this post, and your previous posts in this thread correct, my LN model LBP2180 alt, is a non-duvac alternator, which can be replaced with any non-duvac that fits? It has 3 small studs on the back, with no wires attached! Link to comment Share on other sites More sharing options...
waterskier_1 Posted January 5 Share Posted January 5 14 hours ago, 96 EVO said: Rick, if I'm reading this post, and your previous posts in this thread correct, my LN model LBP2180 alt, is a non-duvac alternator, which can be replaced with any non-duvac that fits? It has 3 small studs on the back, with no wires attached! I believe this is correct for that part number. That alternator is not DUVAC and does not have provisions for an ALT-FAIL circuit. I'm traveling this morning, but I'll see I'd I have drawings to see if you need the ALT-FAIL circuit, which would connect to one of the 3 small studs on the back. - Rick N Link to comment Share on other sites More sharing options...
96 EVO Posted January 5 Share Posted January 5 (edited) 12 minutes ago, waterskier_1 said: I believe this is correct for that part number. That alternator is not DUVAC and does not have provisions for an ALT-FAIL circuit. I'm traveling this morning, but I'll see I'd I have drawings to see if you need the ALT-FAIL circuit, which would connect to one of the 3 small studs on the back. - Rick N Rick, I have an alt/charge lamp in the instrument cluster, but, oddly enough, it never came on. I was made aware of the non-charging issue when my engine warning lamp illuminated. Aladdin confirmed chassis voltage was at 11.9V. {edit} Ok, just checked. Alt/charge lamp doesn't illuminate when you first turn key to ignition position. Likely installed a instrument cluster from earlier years when it was active. Edited January 5 by 96 EVO Link to comment Share on other sites More sharing options...
waterskier_1 Posted January 5 Share Posted January 5 6 hours ago, 96 EVO said: Rick, I have an alt/charge lamp in the instrument cluster, but, oddly enough, it never came on. I was made aware of the non-charging issue when my engine warning lamp illuminated. Aladdin confirmed chassis voltage was at 11.9V. {edit} Ok, just checked. Alt/charge lamp doesn't illuminate when you first turn key to ignition position. Likely installed a instrument cluster from earlier years when it was active. Or the lamp is burnt out Link to comment Share on other sites More sharing options...
96 EVO Posted January 5 Share Posted January 5 1 hour ago, waterskier_1 said: Or the lamp is burnt out True, but with no wires connected to the 3 small posts on the alt, and no 6V relay in the FRB..... Link to comment Share on other sites More sharing options...
96 EVO Posted February 9 Share Posted February 9 Have a little over 100mi on my replacement Delco-Remy alternator. No issues! I did see voltage drop to 13.4V for a second, but quickly bounced back to 14.0V. Link to comment Share on other sites More sharing options...
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