So I have a 1991 4Runner with some sort of electrical problem. About three weeks ago, my electrical system shut down while driving. It was like I was driving with a bad alternator as my light would dim while driving at night. I checked the connections and everything seemed good. That sounded weird to me, so I took my battery and alternator into Autozone to be tested. They said that it was the battery, so I bought a new one and thought that was the end of it. But the problem didn't stop. It is like the alternator works only a third of the time. My new battery is strong enough to take it for a while, but I don't know what is wrong. I watch my battery meter on the dash go back and forth from charging to battery power. Again the connections look good, but has anyone had these symptoms happen before? Or maybe the alternator is going bad and just happened to work for the test?

 

We had something similar happen on our Jeep. On and off for about a week, then just off. The alternator went and fried the battery in the process - save your new batt. and replace the alternator

 

Replace the alt. Simple way to figure it out: Turn car over, let run with highbeams, blower and A/c on full blast. If she shuts off at all its the alt..

 

So the alternator is toast. Anybody have any suggestions as to either an upgraded alternator or aftermarket alternator? Or do I just save my money and buy new brushes and call it good?