Alternator Light on a Subaru

I have a '99 Subaru Legacy (loaded) with 127k. Fourteen months ago I had an alternator go. I took it to a recommended (trustworthy) shop and they put in a NEW alternator. After about 6 months the alternator light started coming on again.



I took it to the same shop and they told me everything was fine. It’s still lighting up (with the BRAKE light, could be gage light overflow) AFTER the engine warms up. If it’s like -10?F it’ll take ~20 minutes, in the middle of summer about 5-7 minutes. I JUST replaced the battery last week and it fixed the light all the way home, but started up again on the next trip. AutoZone tested the system and said everything tests fine.



This is getting frustrating and I just want to trade it for a newer van, but need it to be on its best behavior so I can get a trade value for it.



Help!

With the combination of the alternator warning light, the brake warning light, and the recent need to replace the battery, I would say that there is about a 99% probability that the alternator is about to give up the ghost.

You had better get it checked out by a different mechanic’s shop before you kill the new battery and wind up stranded in an inconvenient location at an inconvenient time.