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?

dead short somewhere
 

There is a spark when you connect the cables. I don't have much in the line of testing equipment... just a test light. I will go disconnect the voltage guage and let you know what happens. thanks.

If its the volt gauge it should spark..........no spark then the problem is somewhere else

dead short somewhere
 

Sorry if this sounds stupid.... but do you mean when I unhook the voltage guage, IT will spark?

Normally it will not spark, if it does its likely the problem

Just thought of the cigarette lighters, have had a couple that caused a draw over the years

I doubt it's the gauge. a bad gauge would give a false reading but not drain all the batteries down. you have something drawing juice big time. there have been more than one ocassion where i left my 2 dock lights on over night for 14 hours & my truck started as if I left nothing on. no noticeable affect on starting at all. if you take the pos cable from the starter & touch it to the first battery & get a good spark, then something is pulling juice. one thing to consider... since it's draining with the truck off you can eliminate a lot of guess work.

it has to be something that could draw with truck off. it's not going to be anything that requires the ignition switch on. example... it is not going to be the heater, a/c, radio, whatever turns off with the key is not it. it is something that can function with the key off, like headlights, cig lighter, dome lights, e.t.c or the wiring going to or from them is where you will most likely find the short. the starter or alternator, would i.m.o not be it either cause they have no function when truck is off. a wire going to or from, could be the prob, cause they branch off & go to differernt areas. but not the alt or starter in & of itself. have you checked the 2 pos wires going from the alt to the regulator ? your prob is a hot wire somehwere. i.m.o.. I really wish I could be of more help. :sad:

is the truck hooked up to a trailer ? like i said earlier.. it is something that can be operated while ignition off & traler lights & the pig tail connection can get power with key off. if it's just the truck than you have less to go over.

dead short somewhere
 

Is both sides of the amp guage supposed to be hot with the key off?

on my truck I have a volt gauge & when i turn key off gauge goes dead. ( all the way to the left) when i turn key on it jumps back up. i have an intl, so my gauge will be diiferent. ign turns on a lot of accessories & should also turn off all those accessories when it is turned off.

An Amp guage will be hot on both sides, a volt guage has a Pos & a Neg. You could try unhooking the wires from the amp guage & see if it sparks, that would indicate a draw.

post when you get problem solved. some one will need the info.

Re: Dead Short somewhere
 

A quick & easy fix is to install a master disconnect switch to open the main supply when you park the truck overnight.

Or... remove your battery cable and connect a test light between the cable end and battery post. It will light up when there is current draw present; start removing fuses and disconnecting loads until the light turns off.

It would be a good idea to measure how much as well.

dead short somewhere
 

I'm still looking for the short... I will post when I find it. Another feller told me the other day to put a manual disconnect on it for over night as well.. and I may end up having to do that, but I sure would rather find the short and fix it. I have found a toggle switch smoking.. got new ones to install yesterday, but haven't got them in yet, so I dont' know if that was possibly the problem yet or not. I'll keep in touch. thanks for the help, any more ideas please let me know!

Re: dead short somewhere
 

Quite often, when the smoke "comes out of the switch", it is caused by a shorted load that is controlled by the switch.

...what is the switch for??

sterling lt9500
 

we are kinda having similar shorting out problems with our 2000 sterling LT9500. heater fan switch burns out (this is the second time now);lights dim auto when driving down the road;when using blinker light auto go from high to low beam and there is a little crackling; speedometer and odometer only register at about 2/3 when raining or snowing. anyone have anyideas. have already checked several grounds, but don't have a schematic to know where ALL the grounds are. and big truck repair companies have been no help because they havent a clue.