Toyota Repair: Charging System Trouble - Alternator Tested Good?, alternator brushes, bench test

Question
I have a '94 4Runner and the charging system isn't working. The Battery, Brake, and Transmission Temp light are on.

We had O'Reilly's test the Alternator and they said it was giving a charge (they couldn't test the diodes). Battery tested marginal.

When we check Voltage at the battery terminals with car at idle we get 12V. We did put another battery in (not new) and got the same reading.

When we put the original battery in a different vehicle we got a 13V reading from it. That vehicle's own battery tested higher.

We checked fuses with VOM and all are working. We did find a red wire by the inside kick panel fuse box that isn't attached anywhere. It's coming from a group of wires running under the carpet under the pedals and has a fuse link. (?)

We replaced the Alternator Brushes (one had a damaged spring).

Battery connection terminals do look like they need replaced but Dealership said that wouldn't be the cause of the dash lights.

We're 85 miles from the dealership and don't want to tow it that far if we can help it. :-(

We have had a few backlighting lights on our AC panel blink in the past. They'd turned off and if you tap or wiggle the AC switches the lights would come on so we're wondering/worried about a short.

Thanks,
-Elizabeth


Answer
Electrical problems are the most difficult to deal with here, mainly because there are certain test and wire tracing that sometimes needs to be done to locate the problem, the only help I can offer at this time is to try replacing the alternator anyway, if there are only 12 volts across the battery terminals with the engine running the alternator is not charging the system, this is the reason all those lights on the dash are on, even though the bench test of the alternator said it's good it may not have been tested with enough of an electrical current draw on it, invest in a rebuilt alternator and it will probably solve the problem.