I had a situation a few years ago with an Autozone alternator. After installing and finding it didn't work, then doing the same thing with the replacement, the third time I went to the store I had them test the rebuilt alternator before I took it home. It charged up a storm, and I never had a lick of trouble with it. Check the new alternator before you leave the store.

I have gotten bad rebuilts from Autozone and NAPA. I paid more for the NAPA and it nearly burned my truck. When this alternator failed there were foot high flames shooting out of the alternator.
I am trying to say that no parts house has a corner on the defects market.

R.