Hello all.

Long time lurker here, but today I finally took the time to register. I own an 87 toyota pickup on 35/14.50/15 gumbo monster mudders. When I break something I am usually good about fixing it, but the following problem just has me stumped.

About a week ago I noticed my battery going completely dead. I had the alternator tested and it registered bad, and since the battery was really old I went ahead and replaced it as well. Drove it around about a week during the daytime, and the truck was holding it's own. After a night of driving, I noticed my headlights getting more and more dim until the truck finally died. The next day I charged the battery up, started the truck and let it run for about 5-6 minutes, then took the negative side off the attery and the truck promplty died.. alternator wasn't charging. Took it off, and has it tested thinking I may have gotten a defective one, but it registered out perfect.

That's where I am at right now. I am stuck on what to do. I have checked the wires as best I can, and they all seem to be fine. Is there a fuse or something somewhere that I am missing? Any info at all would be greatly appreciated.

Rob

 

check the fuse box next to the battery and there should also be a "fusible link" somewhere along the main output charge wire on the alt.


With a voltmeter and the truck idling measure the voltage at the battery.....since yours is not charing there I expect you will measure 12.4 volts.
With it still idling measure the actual output of the alternator. I think it's a thick white wire on the back. If it measures 14.2 then the alt is good and you likely have a break in that wire somewhere....if you measure only 12.4 or so then the alt is either bad or the harness that attaches to it has an issue.

 

In the older rigs, grounding commonly becomes a problem. Do a search on here for some of the remedies and I am betting you find an answer to your problem.

Welcome to YT.