Bad Alternator?

Discussion in 'Chevy Trailblazer Forum (GMC Envoy)' started by jbaniaga, Nov 30, 2010.

  1. jbaniaga

    jbaniaga New Member

    2006 Chevy TB

    Recently noticed that the battery gauge on my cluster will fluctuate from the normal 14, DOWN to the line between 9 & 14 in parked gear. In drive, while at stop lights or stop signs, the car starts to pulse and the battery gauge starts to pulse down as well. At night, the lights also fluctuate as if power was being drained. The battery checked fine, but was wondering if it could be the alternator as well as how easy is it to D-I-Y?
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Sound like the alternator. They are a pain in the a** to change on a 4.2 Trailblazer, the bottom bolt.
  3. kelonthomas74

    kelonthomas74 New Member

    I have a 06 Trailblazer with the same problem. I was told it was the alternator so I replaced it. Turns out I still have the same problem. Its fine as long as I'm driving but as soon as I'm sitting still my lights start to dim & the motor revs up & down. I'm starting to think its in throttle control because as long as I'm at 700 rpm's its fine but as soon as it drops to 500 I start having problems.

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