Epic Alternator Failure

[Alucard-HD]

Well i fix one issue and another issue appears. Me and some friends were driving my M1008 to a hobby store last night and on the way there i noticed my voltage meter was on the border line of green and yellow i figured it should be ok and i'll look at it when i get home. When we left the hobby store the truck was dead. I had the truck jumped with a jumper pack and it started up. As we drove home my head lights were gone and the meter was now pinned in the red. I had to stop and let the truck idel for a few minutes to get some power back to my lights and later met up with a friend of mine to light the way for me. The question is how can both alternators take a crap? I guess anything is possible. Do the CUCVs use a different type of alternator, or will one form a civy 6.2 work and i'll just buy 2. good thing it was a diesel or i would've had to be towed.

 

[ODdave]

i dobt both alts are bad, b/c they are wired in series if one fails the other cannot function

 

[Ruppster]

Well, as some will point out the search feature is your friend. The charging system on CUCV's is a common subject on this forum. Just keep in mind a CUCV has two seperate 12 volt charging systems to make 24 volts. Since each alternator is only 12 volts they have one key feature called an isolated ground that allows them to be wired together to make 24 volts. The glow plug system and starter are the only parts that use 24 volts. This is so a 24 volt 6x6 can jump start a CUCV. The main part of the electrical system of the truck is set up for 12 volts, just like a civilian Chevy truck. If your lights were going out then you at least have a problem with the alt on the driver's side. This alternator does not need to have an isolated ground so a civilian alt could work in this position if need be. It's the alt on the passenger side that MUST have an isolated ground.

Best bet would be to find a auto electric shop and just have them test and rebuild what you have instead of trying to find the correct alternators with an isolated ground.

As far as the engine still running due to being a diesel remember that there is an electricaly activated soleniod that shuts off fuel to the engine. It might be a diesel engine but if you drop enough voltage that fuel will still shut off.

On another note did you score anything good from the hobby shop?

Ruppster

 

[Alucard-HD]

Well, as some will point out the search feature is your friend. The charging system on CUCV's is a common subject on this forum. Just keep in mind a CUCV has two seperate 12 volt charging systems to make 24 volts. Since each alternator is only 12 volts they have one key feature called an isolated ground that allows them to be wired together to make 24 volts. The glow plug system and starter are the only parts that use 24 volts. This is so a 24 volt 6x6 can jump start a CUCV. The main part of the electrical system of the truck is set up for 12 volts, just like a civilian Chevy truck. If your lights were going out then you at least have a problem with the alt on the driver's side. This alternator does not need to have an isolated ground so a civilian alt could work in this position if need be. It's the alt on the passenger side that MUST have an isolated ground.

Best bet would be to find a auto electric shop and just have them test and rebuild what you have instead of trying to find the correct alternators with an isolated ground.

As far as the engine still running due to being a diesel remember that there is an electricaly activated soleniod that shuts off fuel to the engine. It might be a diesel engine but if you drop enough voltage that fuel will still shut off.

On another note did you score anything good from the hobby shop?

Ruppster

Thanks for the Info I'll take a look. I think i'll take the alts off and have them checked. At the hobby shop, I had to order parts for my Losi High Roller I broke some things lol.

 

[dstang97]

Any of the Gen lights on?

 

[Alucard-HD]

Any of the Gen lights on?

Nothing. Every light on the truck lost power. The only light that stayed on what fasten seat belts. I found that odd but the Volt gage was pinned in the red. Even my high beam indicator lights on the dash, the little blue dots, dimmed out and gone.

 

[dstang97]

disconnect both batteries and charge them up. Then reinstall. Turn the key to run both Gen 1 and gem2 should light up. Do that and report back.

 

[319]

Did you jump the front, rear, or both batteries?

 

[Alucard-HD]

disconnect both batteries and charge them up. Then reinstall. Turn the key to run both Gen 1 and gem2 should light up. Do that and report back.

I have in the past. The Gen 2 light stays on awhile. Gen 1 Never comes on

 

[dstang97]

Replace bulb or clean contacts on gen light

 

[Alucard-HD]

Replace bulb or clean contacts on gen light

The Gen 1 light has come on before but it doesnt stay on like Gen 2. If i may ask what would i be looking at if i rechaged the batterys and did this?

 

[dstang97]

To give it some power to light up some check engine lights. You need to rebuild passangers side alt. And recharge batteries and then check for 14v at each battery with truck running

 

[Alucard-HD]

To give it some power to light up some check engine lights. You need to rebuild passangers side alt. And recharge batteries and then check for 14v at each battery with truck running

Ok thanks man, what about the driver side?

 

[dstang97]

if you have extra cash have them both rebuilt and fix as needed

 

[Alucard-HD]

if you have extra cash have them both rebuilt and fix as needed

Understood. There is an alt shop right by me. How much does it cost to have one rebuilt?

 

[Warthog]

For everyone (not picking on just you)....

Per the Technical Manuals at the start of the Troubleshooting Section

Quote "c. When troubleshooting a malfunction, (1) Ensure that both batteries are fully charged."

---------------------------------

The alternator rebuilt/testing has been discussed many, many times. Twice this week already.

Rebuilds run from $50 up to $250. Depends on the shop.

You can even buy new or rebuilts off ebay or NAPA.

Part numbers are listed in the CUCV Wiki and the FAQ thread on the CUCV Forum.

Autozone, Oreilly's, just about any parts shops can test them. Just tell them that to hookup the ground lead to the "ground terminal" and not the case.

The light bulbs for both alternators are required to be functioning inorder for the alternators to work. They are part of the ignition power circuit that "excites" the windings to make the alts produce power.

No Bulbs, No worky

 

[Alucard-HD]

For everyone (not picking on just you)....

Per the Technical Manuals at the start of the Troubleshooting Section

Quote "c. When troubleshooting a malfunction, (1) Ensure that both batteries are fully charged."

---------------------------------

The alternator rebuilt/testing has been discussed many, many times. Twice this week already.

Rebuilds run from $50 up to $250. Depends on the shop.

You can even buy new or rebuilts off ebay or NAPA.

Part numbers are listed in the CUCV Wiki and the FAQ thread on the CUCV Forum.

Autozone, Oreilly's, just about any parts shops can test them. Just tell them that to hookup the ground lead to the "ground terminal" and not the case.

The light bulbs for both alternators are required to be functioning inorder for the alternators to work. They are part of the ignition power circuit that "excites" the windings to make the alts produce power.

No Bulbs, No worky

Ok, Thanks man

 

[CUCV85]

if you have extra cash have them both rebuilt and fix as needed

He does need to charge up the batteries, turn the key on and both gen 1 LEFT (Drivers Side) and gen 2 RIGHT (Passengers Side) lights should come on as soon as he turns the key. Just like you stated. As we know he must have the light come on for both sides, for the bulb has to work for the Alternators to Work!
It's weird we know this but he doesn't. You might have to pull the dash to clean the circuit board where all the lights plug (well twist) into. There are posts that cover this with pictures about how to clean, what to look for as far as broken copper in the board and how to repair if need be. Like I said the bulbs must work in the GEN 1 and gen 2 sockets or no charge up. I found this out. While you have the dash out if you do this - clean it all including all the bulb sockets. Clean with a sharp knife on the socket tabs -be very careful, you'll see what I mean. Use a small piece of say Emery cloth and use a pencil eraser to clean the flex board that has copper going to the sockets. Don't forget to clean the harness plug in. Again you'll see what I mean. Now change all the #194 bulbs. Report back.
You may have to rebuild and alternator AKA generator. I doubt both at once. I know if you been driving it around without GEN 1 (drivers side) alternator not charging of course your trucks 12v system isn't going to last long. The drivers side operates the trucks lighting system,example headlights. The passengers side charges the rear battery it's a 12 volt alternator hooked up in series to the other alternator (gen1) to add to 12 volts to bump the charge up to 24 volts. 12v gen 1 + 12v gen 2 =24volts.
I have had a belt I bought that was to long. I had the adjustment all the way to the end and when I rev-ed the truck to say climb a hill the gen 2 light would come on. I was OK because the gen 1 was still charging and I could use my headlights.
Like 10 min would go by, I would stop at a stop light for say, the truck would idle down and the gen 2 light would go out. I believe it's because "the alternator could catch up the engine at an idle. Ultimately you must have 2 decent batteries, 2 working alternators with belts not over tightened but secure to charge your SYSTEM. Some guys change the pulley on each alternator because they're worn so bad. Most of the time a correct belt that is tightened correctly on these will work just fine. It's not like we're working them, geeze they're 100 amps each!

 

[Alucard-HD]

He does need to charge up the batteries, turn the key on and both gen 1 LEFT (Drivers Side) and gen 2 RIGHT (Passengers Side) lights should come on as soon as he turns the key. Just like you stated. As we know he must have the light come on for both sides, for the bulb has to work for the Alternators to Work!
It's weird we know this but he doesn't. You might have to pull the dash to clean the circuit board where all the lights plug (well twist) into. There are posts that cover this with pictures about how to clean, what to look for as far as broken copper in the board and how to repair if need be. Like I said the bulbs must work in the GEN 1 and gen 2 sockets or no charge up. I found this out. While you have the dash out if you do this - clean it all including all the bulb sockets. Clean with a sharp knife on the socket tabs -be very careful, you'll see what I mean. Use a small piece of say Emery cloth and use a pencil eraser to clean the flex board that has copper going to the sockets. Don't forget to clean the harness plug in. Again you'll see what I mean. Now change all the #194 bulbs. Report back.
You may have to rebuild and alternator AKA generator. I doubt both at once. I know if you been driving it around without GEN 1 (drivers side) alternator not charging of course your trucks 12v system isn't going to last long. The drivers side operates the trucks lighting system,example headlights. The passengers side charges the rear battery it's a 12 volt alternator hooked up in series to the other alternator (gen1) to add to 12 volts to bump the charge up to 24 volts. 12v gen 1 + 12v gen 2
I have had a belt I bought that was to long. I had the adjustment all the way to the end and when I rev-ed the truck to say climb a hill the gen 2 light would come on. I was OK because the gen 1 was still charging and I could use my headlights.
Like 10 min would go by, I would stop at a stop light for say, the truck would idle down and the gen 2 light would go out. I believe it's because "the alternator could catch up the engine at an idle. Ultimately you must have 2 decent batteries, 2 working alternators with belts not over tightened but secure to charge your SYSTEM. Some guys change the pulley on each alternator because they're worn so bad. Most of the time a correct belt that is tightened correctly on these will work just fine. It's not like we're working them, geeze they're 100 amps each!
=24volts.

Thanks for the info. When i get a chance to work on the truck i'll report back.