Hello --

I have a 1986 4x4 truck -- 22R engine, 5 spd trans, no A/C, 307,000 miles. Lately it blows the 15 amp fuse marked "ENG" in the under-dash fuse box. I lose the charging circuit ("Charging" light goes on and volt meter shows about 12 volts when running) and the turn signals. If I replace the fuse, even temporarily with a 20 amp fuse, it blows again right away. Could this be an alternator or voltage regulator failure or what? Thanks.

 

You could test your alternator and see what kind of voltage it's putting out, but it sounds like you have a short somewhere.

 

Check and make sure that your grounds are gronded , and check everywhere for cut frayed or lose wires

GOOD LUCK

 

It did turn out to be a short in the backup light switch. The backup lights and about 5 other circuits are on this same fuse. Thanks.