Weird Electrical?

Discussion in 'Audio & Electronics' started by PNWMuseumman, May 16, 2018.

  1. PNWMuseumman

    PNWMuseumman Bow Ties Are Cool Supporting Member

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    TL : DR → Headlights dim and blower speed slows (only when set to highest setting) at idle, then brighten / speeds up when under throttle. Changing the alternator didn't fix.

    For a while now I've noticed that my 02 Denali's headlights and dash will dim ever so slightly at idle, then brighten up when you step on the throttle. Also, when on the highest setting, the AC blower motor will slow a surprising amount at idle, and speed back up when you throttle up as well. I thought this was a sign of a weakening Alternator. Over the Mother's day weekend, the alternator died. I limped home on just the battery, then replaced the alternator and the battery. The truck starts and runs great now, but it didn't solve either of my dimming / blower speed issues. What else would cause those to happen?
     
  2. sumo

    sumo dn ʇǝƃ ʇuɐɔ & llǝɟ ı

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    Check your ground cables. Rust or loose causing a high resistance.
     
  3. PNWMuseumman

    PNWMuseumman Bow Ties Are Cool Supporting Member

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    Like ground cable off the battery? Or is there another one off the engine/electrical system somewhere?

    Thanks!
     
  4. sumo

    sumo dn ʇǝƃ ʇuɐɔ & llǝɟ ı

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    Yea make sure your ground cable is secure and tight. Also make sure there isn’t battery acid build up on the terminal and post. Then follow the negative battery cable where it bolts to the frame. Make sure that end is clean and tight. You may have to look up a circuit for your headlights and see if there are any additional ground points in that circuit and check those as well.
     
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