BJ74 Electrical Gremlins

[13bt]

I'm about to sell this thing, its driving me crazy. Here is how it goes:

Everything is fine and out of the blue(I havent hooked up any new accessories) my battiers start to drain by themselves. So whenever I park the truck I have to take the + lead off of the battery. This is the only way I can keep a charge while it is parked.

This drain is VERY fast...2 fully charged batteries will drain down to around 9-10 volts overnight, If I hook up my multimeter I can watch the volts go down by .01, quickly too maybe about every 15-20 seconds? What could cause such a fast drain on the batteries? Im guessing that the ignition is toast because when I take the + terminal off the battery while its running the truck will die(yes it is a diesel, it used to run w/o batteries). It has a 24-12V converter for the stereo that I have unhooked which didnt do anything, all the lights are off and none of the switches are jammed or stuck. It has 2 newer batteries maybe a few months old...optima reds too, maybe thats my prob?

I also have the charge light coming on when the rpms are low and just yseterday most of the dash lights came on dimly(im guessing cause of low batteries) and when I have the highbeams on and use the signal the tach and singal lights go crazy.

Looking for any ideas out the im losing my mind!

Thanks guys

BTW: 1989 BJ74 13BT w/ 4spd Auto

 

[GoatboyNZ]

ok this is just off the top of my head with out looking at any manuals. anyone feel free to correct me if im wrong but if the engine dies when the postive lead is disconnected from the batterys tha t will mean that the alternator is not putting out any juice. with out juice the solenoid in the edic will put the fuel pump into the stop position and the engine will die.
As for the alternator, there is a wire coming from the batteries to supply voltage to excite the rotor to induce a electromagnetic current in the stator winding thereby creating voltage.
if there is a short in the regulator/rectifier pack( i think) on the back of the alternator this will stop the excitation of the rotor(no charging) and also drain the batteries.
like is said this is off the top of my head and im all rusty on electrickery but i hope it helps. check with a multimeter so see if you have voltage coming out the back of the alternator.

 

[John Galt]

Post the question here:
Diesel Tech and 24 volts Systems - IH8MUD Forums
to get more answers.

 

[13bt]

Thanks goatboy ill try that for sure, I assume you mean check the voltage reg? it has an external regulator mounted on the fender not a IC type on the alt like most cars. Ill check that out

Any chance somebody could move this thread to 24v tech?