I'm hoping one of you had this problem with your 4X4 Blazer. My dash gage started dropping to 5 volts and jump back up to about 15 volts every once in a while for the pass 2 months or so. My lights would dim out as well, but it would always jump back up to charging after a few minutes. The other day I took it to AutoZone and had them test it and they said the battery had a bad cell, I bought a new battery and had them put it in. I drove home and the darn thing started doing the same thing again. Drove back to AutoZone and said the volt gage on the dash was still dropping. Then they said it would be best to test the alternator out of the vehicle. I drove back home so I could do just that. Took the alternator back to AutoZone and had them bench test it, it showed good. Went back home and reinstalled it, started charging again and after a couple minutes the volt meter dropped again. Then I drove to Advance and had them test it in the vehicle, showed not charging at all. Also had them do a code check, nothing came up. Can somebody please tell me what's going on with my charging system. One minute the alternator is charging and the next minute it isn't. By the way, the alternator is still under a year old and AutoZone won't give me a new one if it's showing good.

 

Bad alt, Just because these people work at these stores it doesnt mean they`re smart

 

I'm gonna make AutoZone test it in the vehicles, like Advance did. It showed bad for Advance. I check and re-checked all my wires, even with a wire testing meter. This darn thing is still under warranty for 4 more months.