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I posted before on a battery drain issue and still haven't found the problem so I'm brainstorming for anything that might help on how to find the cause. Truck is an '89 Bronco - 351fi/C6 combo. Drain at battery is around 1.3 amps.
The #5 circuit (turn signals & backup lights) is drawing the power because the test light goes out when I pull that fuse. #9 circuit (heater/ac) is also hot and works without key. Both are switched circuits and I already messed with the ignition switch adjustment without success. I actually pulled the switch out entirely and both circuits still were powered.
What tips and tricks are there to finding what's causing power to switched circuits to be there full time? I'm about at the end of my rope...
Get in the fuse box with a testlight or meter, and check for voltages with the key off. Make a note of what's hot and what's dead and make a list for us. Also in the list, if you have any dead fuses, turn the key on and see if they become hot.
If we have a random, some fuses work with the key, and some don't and stay hot all the time, I am thinking you had a problem somewhere along the way and a group of wires in a bundle may have melted together. Some testing will help narrow it down.
I'll do some more testing tonite. I've checked over everything I could think of but hadn't yet started cutting open the wiring harness under the hood to look for wires that melted. I guess it makes sense that if a group melted together with a wire that is always hot it could cause this problem. I haven't seen any obvious evidence of a section having melted so I'm guessing I'll just have to start opening the harness and work backwards toward the battery.
It's still weird to me that everything works just as it should and no fuses are blowing or anything either.
Aargghh- this is getting to be a real pain but I want to do everything in my power before I take it somewhere and pay to get it fixed. This kind of stuff takes time and can get expensve real quick.
I am thinking we need a picture of what's going on. The fuse box is divided into two major parts; hot all the time circuits, and hot with the key on circuits.
If all the hot with the key on fuses are hot with the key off, I would double check the ignition switch or it's wire again.
If only some of the hot with the key on fuses are hot all the time, and the others work normally, then we can make a list of the ones at fault, and it might clue us in on where the wiring problem may be as far as physical location.