1999 Trailblazer Alternator Trouble

maudit87maudit87 Member Posts: 20
edited May 2014 in Chevrolet
Hi all, my dad has a 1999 Chevy Trailblazer and the alternator went in it. He replaced and just days later it went again. He's a certified mechanic (works on cranes, dumptrucks, you name it), he baffled about it. He's gonna get a new one just incase the "new" one was faulty, but are there any problems with the electrical or any that could be doing this in that year model. It's got about 120,000 miles on it. I didn't see anything about recalls when I googled it.


  • jlflemmonsjlflemmons Member Posts: 2,242
    Just make sure the battery doesn't have a shorted cell. That will cause the alternator to run high output trying to charge.
  • maudit87maudit87 Member Posts: 20
    Thanks for the reply, I'll let him know to get that checked out.
  • twmddstwmdds Member Posts: 1
    This started 2 yrs ago with headlights dimming while coasting. Dealer replaced the battery, but no improvement. Then waterpump went out so they put in a new waterpump and alternator (they said the water leaked and ruined the alternator). Then still some headlight dimming while coasting. Then the new (2nd) alternator went out and was replaced a couple of weeks ago. Today the battery light is back on so I took it to the dealer, but haven't yet heard from them. Are these really bad alternators - poorly made - or something else????
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