Electrical problems

[1986RangerXL]

I have a '87 Ranger with the 2.9L v6. One night I put the battery in backwards and reversed the cables, I noticed the fusible link started smoking and immediately pulled the cables off. No interior electronics or fuses are blown or have any problems. When I use a test light, all the fusible links still conduct power. However the truck has grown a liking to draining batteries like it's nothing. I put a different battery in thinking the battery was fried but same result. The truck will start right up with a fresh battery but after some use will outright refuse to turn over. What can I do?

 

[RobbieD]

Sorry to hear about your bad luck. First you'll have to isolate and identify what electrical component's been damaged, and repair or replace accordingly. You'll probably need a volt meter (DMM- digital multi meter or an old-school analog volt meter), and a wiring book (EVTM) for your truck will help immensely.

In the meantime, try disconnecting the battery NEG cable; put your test light between battery NEG post and the removed cable end. If your parasitic current draw is big enough (yours may be), the test light will light, even though it may be just a small glow on test light bulb filament. Then start pulling your fuses, one at a time, until the test light goes out. This will help you isolate where the damage is, and you can go from there. When the engine does crank and run, does it show that the battery is charging?

 

[Snoranger]

If I had to guess, I’d say you needed up the alternator... hook a charged battery up and see if the alternator is getting hot/ warmer then everything else around it.

 

[1986RangerXL]

Sorry to hear about your bad luck. First you'll have to isolate and identify what electrical component's been damaged, and repair or replace accordingly. You'll probably need a volt meter (DMM- digital multi meter or an old-school analog volt meter), and a wiring book (EVTM) for your truck will help immensely.

In the meantime, try disconnecting the battery NEG cable; put your test light between battery NEG post and the removed cable end. If your parasitic current draw is big enough (yours may be), the test light will light, even though it may be just a small glow on test light bulb filament. Then start pulling your fuses, one at a time, until the test light goes out. This will help you isolate where the damage is, and you can go from there. When the engine does crank and run, does it show that the battery is charging?

The battery guage in the dash doesn't move, I assume it doesn't work. The battery doesnt act like it is being charged though. I did a lot of digging and it sounds like there are fusible links going to the alternator that may have burned up. Just gonna have to test and replace like you said

 

[1986RangerXL]

If I had to guess, I’d say you needed up the alternator... hook a charged battery up and see if the alternator is getting hot/ warmer then everything else around it.

My first guess as well, I just rebuilt the alternator so hopefully it's just the fuses..