Dead Short somewhere
 

I have a dead short somewhere in my 1984 Peterbilt. I replaced the starter, because the parts store said it had a short in it, but it did not fix it. When you hook up the battery cables, the voltage meter goes up, and drains the batteries. I have searched and searched for this, trying every single light, etc, and havent' found it yet. Can anyone give me any ideas??? Please help! thanks. preachertom

volt meter goes up as in over charge ? drains batteries when engine off or running ?

dead short somewhere
 

the volt meter goes up to about 12, and drains the batteries when the engine is off.

I've been fighting the same thing on a 1995 3406E. Mine is messing up my A/C. All I know to do is test with a KD tester. It's frustrating. Good Luck.

12 volts seems low to begin with. mine is on 14 un less I put everything on, then it drops but never below 13 volts. is your volt meter needle constantly shaking back & forth ? batteries need to be checked. alt could also have a short too. it needs to be checked. battery testers can be bought at harbor freight for 20-25.00.

all cables connecting battery to battery should be looked at carefully. also & especially the positive cable to the starter along with the ground cable. a lot of these cables will corrode from the inside & you wont even see it from the protective coating outside. if jumper cables (the ones from batery to battery) are stiff, they need replacing. I replaced mine not long ago due to a short. the long pos cable cost me $20.00 to be made up. it was corroded real bad under the coating, but by looing at the outside it looked fine. I am not a mechanic but have diagnosed & fixed lots of things on my truck. I hope this helps you.. keep us posted.. good luck. :D

dead short somewhere
 

I have put new batteries in and I've checked the alternator, and put a new starter in, and still have the same problem. Any more ideas?

How long does it take to drain the batteries? Try pulling all the breakers or fuses out of the panel & see if it still drains the batteries. Maybe leave the alternator disconnected as well. How long have you known the truck & is it a new problem? Has any work been done to the elctrical lately? Or anything been put on the truck....

deadshort somewhere
 

It'll take overnight to drain the batteries. I did disconnect the alternator, and that didn't fix it. I pulled each breaker out of the panel individually, and that didn't help either. It hasn't had any electrical work lately. The truck had set for 8 years, when I bought it. I've checked out every switch in it, and everything in the sleeper. I'm running out of ideas... Could it possibly be a shorted out voltage guage?
thanks.

deadshort somewhere
 

It'll take overnight to drain the batteries. I did disconnect the alternator, and that didn't fix it. I pulled each breaker out of the panel individually, and that didn't help either. It hasn't had any electrical work lately. The truck had set for 8 years, when I bought it. I've checked out every switch in it, and everything in the sleeper. I'm running out of ideas... Could it possibly be a shorted out voltage guage?
thanks.

It's possible that its the voltgage itself, be unusual but never say never. You could disconnect it to try. Is there a spark when you connect the cables? What do you have for testing equipment?