M1009 lights slowly dimmed to nothing while driving

[chickenwingss]

Last morning I was driving back from work and my headlights and dash lights slowly dimmed to no light at all it was about an hour and a half drive I shut it off when I got back to camp and now it won't start I am guessing one of the alternators quit working it is still set up for 24v is there anything that generally causes a problem like this I am going to charge my batteries and get a volt meter on the batteries in the mean time I did quite a bit of thread searching but couldn't find any similar situations enlighten me with insight much appreciated

thank you,

-Ryan

 

[cpf240]

The drivers-side alternator, GEN 1, charges the front battery, which provides power to all 12v systems in the truck. My guess is that GEN 1 quit working. I would suggest pulling it and taking it in to have it tested. I would also fully charge and then load test both batteries.

Rebuild kits for the alternators are available from places like CUCV Electric. A standard 27si alternator can be used on if it is only installed in place of GEN 1 on the driver's side. GEN 2 *MUST* be an isolated-ground alternator.

 

[Kohburn]

if the lights dim then it means the alternator isn't providing juice and it is running off of battery power only. this can be an alternator problem or a wiring/grounding problem.

 

[chickenwingss]

Thank you very much for the fast response time I am going to pull the battery and alt and have them tested tomorrow i am on my way to work right now I have rebuild kits on there way from cucv electric right now a new starter relay again much appreciated

 

[chickenwingss]

Will a isolated ground alt work the drivers side and where can you get a 27si I have a napa across the street having a hard time finding one thanks aloa lot
ryan

 

[cpf240]

The CUCVs came with isolated ground alternators in both the GEN 1 and GEN 2 spots, though only GEN 2 *MUST* be an isolated ground alternator. It was just easier to stock only one type of alternator.

This is taken from the CUCV wiki:

The Driver side alternator and forward battery does not have an isolated ground. AutoZone Part number
for the DRIVER side alternator is DL7157 (1975 Caddy V8 Commercial Alternator, 100 amps, Ultima -
Alternator Part Number: 01-0136). This Alternator is 78 AMP and works just fine.
The Passenger side Alternator MUST HAVE an isolated Ground. NAPA has a remanufactured Isolated
Ground Alternator. WIL 90014277. Wilson Alternator rebuilds them. Cost ~$220. Just make sure you test
the alternator before you install it. They have had some issues with the rebuilds of NOT being isolated
grounds. 27si Type 100 Series.

 

[chickenwingss]

So batteries and alternators tested out good the when the key is in accessory mode (first click the little round cylinder that mounts on the engine side fire wall makes a loud constant clicking noise when trying to start the starter relay clicks along with that cylinder thing

 

[cpf240]

That rapid clicking is an indication that the front battery is either low, or bad. Even though the voltages look good, it doesn't mean the battery will be able to sustain it under load.

I would give both batteries a full charge, and then have them load tested. Most auto parts houses should be able to do this for you. If you do take them in to be tested, you could also take the alternators in and have them tested as well.

You might try swapping the batteries around. When my front battery was going, I did that and was able to get a few more starts until I got new batteries.

 

[chickenwingss]

Solution - Rebuilt driver side alternator charged both batteries rear was bad moved front batter to back and got new for front Now holds a charge and is running smooth

So far so good thanks for all the helpful input much appreciated!

 

[cpf240]

Thanks for the follow up!