QuestionI found a, what looks like, a pretty informative forum called Steel Soldiers. Here is a link to the manual I found... http://www.steelsoldiers.com/index.php?module=pagesetter&tid=1&page=5 .... the manual that helped me the most was TM 9-2320-289-20. Some of the guys on the forum recommend putting in a battery equalizer and eliminating the top alternator and duvac system altogether, which sounds like a good idea but when I looked at battery equalizers, they run $800. I only paid $900 for the truck, so it kinda seems out of reason. What I am strongly considering doing is eliminating the top alternator and the duvac system and adding one alternator out of my M-1008 to the drivers side and wiring it to charge the 12volt. Do you see any problem in doing that? From what I have read on that forum, the M-1010 charging system is unreliable and expensive. Looking forward to hearing from you again! Thanks, Brad
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Hello Van,
I was able to download a service manual online and following the steps on troubleshooting the charging system, it told me that I needed to repair a circuit between current/voltage regulator terminal A and ignition terminal on current voltage relay. When I traced the circuit I found a diode that was melted/corroded and in pieces that was between the brown and yellow wires. I'm hoping this is the problem. Do you think this could be my problem? And if so, where could I find this diode?
Thanks, Brad
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Thanks Van for your quick response. I did like you said, with the vehicle off my first battery has 12.6 volts. After starting the truck, it had 12.4 volts. The battery does not seem to be going dead when it's sitting, but rather, goes dead while driving. There is a GPFU blower switch and two switches for flood lights. Flipping them on and off seems to do nothing; I can't hear any relays. Next to the headlight switch, there are two switches... one for blackout lights (which I've unplugged the wires from and using that switch to manually control my glowplug relay) and the other for the service light switch. I'm afraid that I have a bad alternator?
Something to think about though, I have bought an '86 1-ton military pickup for parts. It has smaller alternators on both sides of the engine. I don't know if it would be possible to use these on my truck.
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I recently purchased a 1985 Chevrolet 1-ton ambulance. The truck is running great. It has a 6.2 liter diesel engine with 24 volt starting system. I put two brand new batteries in it when I bought the truck and after driving it, the front battery (the 12 volt one) keeps going dead. I read some of the posts on here and have checked the light bulbs on the dummy lights and they are fine. But when the vehicle is running neither one of the lights are on. Most of the posts I've read on here talk about the alternators being one on the driver side and one on the passenger side, however, both of my alternators are on the passenger side. Both alternators have regulators on them that say 28 volt. When I put a meter on the second battery (24 volt) it will check 3 or 4 volts higher so it is charging fine. I have no idea what to do, hoping you can help. Thanks!
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That truck has a very intricate, and expensive charging system.
In addition to the built in regulators, there is another regulator, and an isolator on the left fender under the hood.
I would check the front battery with a volt meter, both before starting the truck, and after, to see if it seems to be charging. Lets assume it is.
So what is killing it?,,, Almost every single thing in the truck is 12Volt, and operated by that front battery.
The starter is the only thing that needs the second battery.
The truck, and the ambulance body both have a bunch of relays for different things. If a relay stays energized, it will drain that battery.
One relay in particular, is in the dash, and controlled by one of those rocker switches near the ash tray.
That switch is marked GPFU, I believe. That is a gas particulate filter unit. Even if the unit isn't working, if that switch stays on, the relay will be energized, and kill the battery.
Another relay is the blackout lights, controlled by a toggle switch under the headlight switch.
I would get in the truck with the ignition off, and flip those switches, and listen real close to see if you can hear a click under the dash.
Then keep the switches all turned off.
Back in the bed compartment. On the drivers side, under the lower bench there are a bunch of relays, for lights mostly. Make sure all are off.
Let me know how it goes.
Van
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Hi Brad,
So yours has the leece-Neville alternators.
The others are 100 amp Delcos.
I am thoroughly familiar with both trucks, and I did convert the Leece-Neville type to be wired the same as the other, but I used Leece-Neville 12 volt/100 amp alternators, so I could use the existing brackets.
Had to cut, splice, and reroute some wires, but it worked fine. Got rid of those high-dollar isolator, and regulator parts inside the left front fender.
But it isn't just an outright swap.
And I assume you listened real close for the GPFU relay?
The manual glow plug control beats trying to find a replacement module.
Van
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Yes, that could easily be your problem.
Go to about any alternator/starter repair shop.
I'd take one of the other diodes. There are about four wires under the hood there with diodes, all taped up.
It is directional when you put it in.
Where did you find an online manual?
Van
AnswerI have also found that 1010 system to be unreliable, harder to work on, very expensive.
I still have one vehicle with it, but first sign of a problem and it's gone.
Not the truck, but the charging system.
I don't think the Delco alternator will fit the same brackets.
But there is a big Leece-Neville 12 volt alternator that will.
I just got two of them for each truck, and wired the trucks like the 1008's.
Took a little cutting, and rewiring, but it worked fine.
Wouldn't take much to get me to change them completely to 12 volt....actually just a starter, and some rewiring.
But I wanted to keep the 24 volt slave cable system for use on some of my heavy equipment.
I also wanted to keep the orriginal A/C compressor bracket and belt system, cause I added aftermarket air.
No luck on the diode?
Van
