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Topic: rewiring Leece Neville alternator properly (Read 2331 times) previous topic - next topic

rewiring Leece Neville alternator properly

The U300 with 6V92TA engine that I purchased last year just lost the alternator the other day. The previous owner had replaced the HEHR Powerline alternator with a Leece Neville that was rebuilt by some outfit that probably installed used parts by the look of it, and rewired the alternator incorrectly according to Leece Neville. I called Leece Neville's technical support phone number and they emailed me a drawing showing me how to rewire it properly, which I did. Now I need to find a wire in the engine bay that's hot only when the ignition switch is on. I checked inside the wire loom with the small wire I presume comes from the inverter because it's hot all the time, but there isn't a second wire in there that's hot only when the switch is on. (darn it) Instead of randomly cutting into perfectly good wires to see which one(s) are hot only when the ignition switch is on I thought it wise to first look at the drawings, ask you guys, and of course call Foretravel in the morning to see if someone has an educated guess ...or at least better than my wild guess! :)

Here is the technical support phone number for Leece Neville alternators. They will help you diagnose problems and locate repair parts and shops. You should keep this phone number in your cell phone if you don't already have it:

Prestolite: (866) 288-9853
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: rewiring Leece Neville alternator properly

Reply #1 –
I just spent the past month fixing mine. I won't get into what was wrong, because it is a long story. Peter Fleming helped me figure out my problem. I learned a lot about the system and can help you out, but I am on vacation so i may not get on the forum regularly.I will back on Monday. Pm me if you still need help.
1988 40ft grandvilla u300 6v92ta 4speed allison

Re: rewiring Leece Neville alternator properly

Reply #2 –
Scott, If you have a rear start panel you can use the ignition hot wire there.  That's what I used on mine when I ran into the same problems that you are describing.  In describing our alternators the correct term is " FOUR WIRE EXTERNALLY EXCITED ALTERNATOR.
Gary B

Re: rewiring Leece Neville alternator properly

Reply #3 –
I don't have the rear start panel. Leece Neville knew exactly what had been done to my alternator by the previous rebuilder. The drawing they emailed me showed the way the rebuilder had miswired it, and how it should be correctly wired. They are very helpful and I strongly suggest anyone with an alternator problem should call the Leece Neville tech service number I provided above before you get into the repair. The alternator repair shops I went to all tried to sell me an expensive new alternator of course, and two of the three lied to me, but I caught them before they got my money... Trust me, call Leece Neville first or that giant sucking sound you hear will be your wallet imploding! :))
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: rewiring Leece Neville alternator properly

Reply #4 –
The main problem is that truck mechanics don't know the difference.  They put a Delco alternator on my rig and cut out and taped up the wire that had gone to the 12v with ignition on source in the nearby wire bundle and jumped the hot post to the excite post to get it to charge.  They couldn't figure out the extra wire so they just cut it off and taped it up!  That worked but created a loop that tied the batteries together as if the boost switch was always on.  Luckily when trying to figure out if my boost switch had failed and changing out good solenoids some folks on this board helped me figure it out.  Also luckily when I was looking I noticed some electrical tape and found where the wire to the excite terminal had been cut away so it was easy to splice back in and run to the excite post on the correct alternator once I traded the auto electric shop my truck shop Delco.
Dwayne Keith
1992 U240
3116/MD3060

Re: rewiring Leece Neville alternator properly

Reply #5 –
The standard Leece Neville alternator is a "four wire remote sense externally excited" alternator, commonly known as DUVAC.  There are a several options for replacement, here's a link to the technical support forum for Leece.  Alternators | Prestolite News 

I replaced mine with a later generation alternator which is self excited - now this does not mean it has jumpers installed on it, it does not- and uses remote sense.  Here's a link to the discussion on that Alternator alternatives 

One thing for sure, Leece Neville (Prestolite, actually)  has great support in the form of a tech forum, literature, and phone support.  There's lots to know about these alternators, and many an RV'er has been tripped up by so called expert alternator shops.  By far the simplest way to deal with them is to have Foretravel install a new one. 
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: rewiring Leece Neville alternator properly

Reply #6 –
Do you have a remote start at the engine as I do on my '99? That could be a source of switched 12v for you.

Re: rewiring Leece Neville alternator properly

Reply #7 –
Creates problems when wannabee engineers or clueless folks do the dumbest things as in rewiring anything, origional seems to work for the average folks ?
The next question, Whatelse has been electricaly screwed up ?

Re: rewiring Leece Neville alternator properly

Reply #8 –
What about the hour meter? That's the only thing I can think of. I don't have a remote start switch.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: rewiring Leece Neville alternator properly

Reply #9 –
...nope, the red wire to the hour meter goes right by the alternator, just inches away, but it doesn't have power when the ignition switch is on, Foretravel said it's only got power when there's oil pressure because it comes from the oil pressure switch and then goes to the hour meter ...they suggested I use the wire to the air dryer heater and put a 6 amp fuse on it, but that's several feet of wire to run, I wonder if anything bad would happen if I used the hour meter wire?
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: rewiring Leece Neville alternator properly

Reply #10 –
Naw, just keep your fire extinguisher handy  :o

Re: rewiring Leece Neville alternator properly

Reply #11 –
Quote from: RRadio –
...nope, the red wire to the hour meter goes right by the alternator, just inches away, but it doesn't have power when the ignition switch is on, Foretravel said it's only got power when there's oil pressure because it comes from the oil pressure switch and then goes to the hour meter ...they suggested I use the wire to the air dryer heater and put a 6 amp fuse on it, but that's several feet of wire to run, I wonder if anything bad would happen if I used the hour meter wire?

Do what Foretravel suggested. I ran a wire from the remote start switch but since you do not have one of these your options are limited. The FT suggestion seems to me to be the best.

The original wire comes from the solenoid panel which, on my U225, is on the driver's side mounted aft of the rear drive wheels on the bulkhead... facing aft. The wire begins at one of the isolation diodes and routes up the back of the engine room bulkhead and through a plastic split-tube over to the alternator. In my case some moron took the sense wire off an alternator and did not tape it but just tucked it back into the tubing. When enough vibration loosed it, the wire fell out and landed on the exhaust manifold. FT had not fused this wire and it drew enough current to start an electrical fire in the engine room. Luckily we were not underway at the time. It took us six months (with winter intervening) to repair it.

Be sure to protect the wire against rodent damage and fuse it!

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: rewiring Leece Neville alternator properly

Reply #12 –
I dug into the big wire loom that the air dryer heater wire appears to go through and found at least three wires that looked just like it (of course) so I chose one at random and lucked out. I don't know for sure that it's the wire to the air dryer heater but it does have power only when the ignition switch is on. I squeezed another wire into the looms all the way from the alternator down to where this wire is and taped the looms back together with black electrical tape all the way back to the alternator. The looms don't appear to be rubbing on anything and they're wound tight with the tape around them. It looks very professional ...now hopefully it'll work! ;D ...I discovered that the exciter wire has a #59 tag on it, which according to the drawings means it is the correct wire from the isolator to the alternator, so now I'm confident I have the alternator wired exactly the way Leece Neville told me to.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)