This is a follow up to my thread "voltage". My truck had a dead battery today and would'nt start. Obviously something is draining my battery. That's why the voltmeter was reading low. I have decent electrical skills, but I can't figure out how to find shorts in vehicles. Am I supposed to read voltage at any terminal at fusebox? I'm getting 11.5 volts at #15 with the fuse removed. Thanks, Rich

 

Sometimes you can pull fuses till you see the voltmeter start reading normal. But this will only work if the short is on a fused circuit. Once you find the circuit with the short then you need to chase the wires where ever they go usually not any fun at all.

 

If you have a digital volt meter. Unhook the negative battery cable. Hook the volt meter positive lead to the battery negative terminal. Hook the volt meter negative lead to the battery cable.

This will show any power being used by the system.

Unhook the lead to the under hood light. Pull the domelight fuse.

If the meter is showing any voltage start removing fuses one at a time. If the power drain drops a lot on one fuse. What ever is on that fuse is causing the problem.

 

Phillip, I did that and it read 11.81 volts. The voltage barely fluctuated no matter what fuse I pulled out (11.79-11.81). Rich

 

Try it with the key on. after your grids cycle.

Also, an old timer taught me to disconnect the neg terminal at night. If she sparks a little when you touch the post, you have a draw.

 

I had a draw in mine, turned out to be the light in the glovebox. the switch was not shutting it off. Pulled the bulb.

 

Trying to find a short you need to read "amps" not volts.

Take the positive battery cable off the battery. Hook an amp meter, or a digital volt inline between the battery and cable. Start unhooking the major items like the alternator and voltage regulator first. Then start pulling fuses reading the meter to see when the amps drop.

 

I know you pulled the fuses but did you remember to pull the breakers (on mine it is cavity 10 of the fuse box)? Power windows and locks sometimes are the culprit.