Carquest offers a lifetime part warranty against defect or failure, as well as Napa. Half of the alternators that you think your getting a good deal on at Autozone are "reman's or refurbs".

They usually don't get thoroughly tested, they get sent to the warehouse and they only run one test on it normally if it doesn't fail, they'll clean it up and ship it out for resale. Most of them are cores and intermittently failed, where as Car quest or Napa (My recommended part supplier) thoroughly load test the alternators and reman the whole unit with the replaceable parts.




You also, may have a bad ground that you might not have hooked up. Sometimes people forget about that single black wire that bolts to the top of the alternator with a 10mm nut. Are you blowing fuses by the way? Also, don't try and re-charge a dead battery on an alternator. It will exceed its duty-cycle from trying to put out to much amperage and it will overheat, resulting in failure. I see it happen with my customers on the daily. Goodluck man.