M1008 electrical gremlins

[DieselStax]

I was hoping someone who has more experience with cucvs could help me out, it a 86 and its my daily driver and I've never had any problems with it. Today I go to start it and one of the battery's was dead. I charged it and go to start and I now have no glow plugs, the light doesn't come on and there's no click from the relay. On top of that my brake lights went out and my fuel gauge stopped working, it shows that I have no fuel yet I have a full tank of diesel. Hoping someone could give me some help. Thank you

 

[kingchr]

Can you tell us which battery was dead (front or rear)? Is this truck still stock (any glow plug mods been done, or a 12v conversion)? Also, can you check for voltage at the glow plug relay on the firewall with the key on? Once we have a little more info, we may be able to help. Also, others will ask so I will just get a head start, have you gotten a copy of the tms (tech manuals) yet? There is a link at the top the page that will let you get a pdf copy free. These manuals have a lot of info, so it's a great idea to have a copy.

Have a good one,
Christopher

 

[txmytx_catahoula]

Start all electrical trouble shooting on theses CUCV's with two fully charged AND load tested batteries. From experience I can tell you that one battery can show 12V, but as soon as you turn the key one put a load on it, it falls to below 6V. Since the CUCV has a hybrid 24V system, all it takes is one battery to muck up the works start the confusion of what's working and what's not. Start simple and work through the trouble shooting section of the TM's. At this stage it could be any of several dozen items causing your issue. Good luck!!

 

[DieselStax]

It was the front battery that was dead. Glow plug setup is stock and it has the original 24v system. I'm pretty sure though that the drive side alternator took a crap, I'm going to replace it with a oem isolated ground alternator and see if that fixes things. Thanks for the help and I have the tms, they are extremely helpful.

 

[txmytx_catahoula]

Thanks for the "after action report"! Keep us updated as to whether the replacement alt is the final fix.