how to find a short

[hilljob26]

my truck will drain the battery down after a couple of weeks of not starting it.there is great shop here in town that i can take it to but i would much rather try to find it myself,what do you guys do to look for this.im sure you will help many others out there as well as me

[DANTIP]

I would first leave the ground connection attached to the battery. Next put a digital multi-meter between the positive battery connection and the positive battery cable. Turn the meter to DC Amps and document the amount of draw you have (probably less than 1 amp). Next remove one fuse at a time and check the amp draw. When the amperage goes away, you have at least found the circuit with the problem. Next I would refer to a wiring diagram and check individual components in the circuit. You should be able to replace the defective component.

Good Luck!

[El Jay]

Originally Posted by DANTIP

I would first leave the ground connection attached to the battery. Next put a digital multi-meter between the positive battery connection and the positive battery cable. Turn the meter to DC Amps and document the amount of draw you have (probably less than 1 amp). Next remove one fuse at a time and check the amp draw. When the amperage goes away, you have at least found the circuit with the problem. Next I would refer to a wiring diagram and check individual components in the circuit. You should be able to replace the defective component.

Good Luck!

I agree. That's the easiest, and simplest way to go.

[Longhorn Man]

I recomend doing the ground side of the battery. The draw will be the same, and the chance of a crash course in arc welding will be avoided.
If the reading stays steady through the test, and all fuses are removed, then go unplug the plug on the alt, then the voltage regulator (if it is still the old external set up) then back under the dash, the horn relay... I think that's it?

Now, BEFORE doing all this... was there anything you installed right before all this started? A stereo, or electric fan kit... or anything at all? Or did it just start happening all of a sudden?
Also... you are sure the battery isn't just a weak battery? you tried disconnecting it and hooking it back up after a couple weeks, and it fired right up?

[haysonj]

I just went through this on the electrical board. I used my multi meter on the battery ground like Longhorn said. My problem ending up being the pink tach wire was not on a switched source in the fuse panel and the battery drained through the MSD box. Took a long time to find it just by eliminating circuits Good luck on the hunt.

[cranman]

I agree to go on the ground side, that was how I was taught. Good luck, electrical t/s can be frustrating but look at the good side, the truck doesn't have that many circuits compared to new cars

[DavesRide]

I agree on the groung side also. While removing fuses make sure you don't turn on any power consuming items or you will have to replace the fuse in your meter. My truck just did this the other day and I unplugged my blower relay and the battery hasn't gone down since. Be sure to unplug it as well as the fuses while checking. One more strange tip. Look around when it is dark and look for a small light on somewhere ie glovebox. Just a thought.

[1fun71]

Well Mike sounds like your truck is screwed so I guess I will have to take it off your hands I will come pick it up on friday

[Longhorn Man]

if your dome light turns on when you open the door... remove the bulb before starting

[DANTIP]

Glad to hear you found the culprit!

FYI, there is no difference between the meter being on the positive or negative side of the battery. The circuit may be made or broken at any point in the circuit with the same result because the current draw is identical throughout the circuit. It was also mentioned that the draw took several days to drain the battery, therefore the current draw through the drain had to be pretty low (below the fuse in the multi-meter).

Removing the interior light bulb was a good suggestion I had not considered.

Good Work!

[Longhorn Man]

he found the problem?
He hasn't even posted since he started the thread.
It is 10 times safer to remove the ground cable... doing it on the positive side is asking for trouble.
Otherwise, from an amp point of view, you are right.