i have a 1987 jeep cherokee 4.0 4wd and my battery wont stay charged. ive replaced the battery (under warrenty) alternator (was bad any way) and tighted the drive belt, so what else can i do? it will last me about 15 miles tops and it will quit on me. some ppl have told me to check the volatge regulator, but i thought it was an internal regulator, is it? if its external where is it? anything will help guys, thank you

 

1. Get a service manual and multitester.
2. Diagnose a problem.
3. Advance auto has a computer to use on a car. It checks:
battery, alternator, starter, cable connections and current leaks.
4. Remove suspected part and ask store salesman to check it. Optional: bring it to a second store to check.

Voltage should be not less than 13.5 with engine running, ac, rear glass defroster and headlights on.
Read service manual, because some cars do not charge battery until RPM are around 2K.

 

Key off, you should have battery voltage at the alternator stud.
Key on, you should have 12 volts or so at the yellow wire in the two wire plug on the alternator. Check that first.

 

I have a 1987 Jeep Cherokee, and replaced the alternator because it wasn't charging. It didn't fix the problem. The idiot lights for oil, and
alternator were not coming on when the key was turned on. The fuel
guage wasn't working, and the hand brake light didn't come on when I had
the hand brake on. The problem was that the contacts on the 7.5 amp
dash guage fuse were bent, and not making contact with the fuse. Turning the key on, and twisting the fuse from left to right to make electrical contact with the fuse slot prongs, while viewing the idiot lights
come back on solved the problem. Using a small bladed screw driver to bend the 7.5 amp fuse slot prongs back together so they would make contact with the fuse when inserted worked for me to fix the problem. I hope this has been helpful to others with this problem, as it was rather puzzling to determine what the problem was.