Charging system problem

[tackett]

My girlfriend's '96 Explorer has a charging problem, and I'm trying to fix it while she's out of town. I don't have access to the manual, so I'm not sure where some things are (and none of the fuses are marked).

Here's the symptoms:
Volt meter goes to "L" and battery light comes on at 3400 RPM while she's two hours from home. As she drives it home, the light comes on at lower and lower RPM. She makes it home, and I assume it's a bad alternator.
I remove the alternator & have it tested (it fails) so I replace it.
Sadly, we have the same problem.
She took it to a shop, where they diagnosed a bad alternator.
I got it back home and had the alternator tested (it passes).

My theory:
The alternator tests OK on the bench but fails while in the truck because the field wire (fuse, fusable link) isn't getting power to the alternator.

In any case, I can't find any fusable link, and all the fuses look good (I checked on the panel located on the side of the dashboard, as well as the Power Distribution box under the hood.

Can anybody out there give me a clue about where to look next?

Thanks,
Tackett

 

[RJDriver]

I'm not sure if this helps, but I had a charging issue on another make and model. My fix involved cleaning the battery terminals and connectors. You may also consider having the battery tested. Good Luck!

 

[BrooklynBay]

Welcome to this forum! The alternator might act up when it runs hot. It happened while she was driving. The alternator was cool when it was on the test bench.