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  1. #1
    Jr. Apprentice
    Join Date
    Jan 2011
    Mukwonago, WI

    Default Headlights dimming when i draw power

    This started today,

    Truck is a 08 Sivlerado 5.3 4x4 extended cab 45k miles. It seems when I apply the brakes, turn signals, windows etc... the headlights dim for a split second and return to normal. Earlier it seemed the headlights would dim and radio go out for a split second when no brakes, blinkers etc were applied, but that seemed to stop happening after i was about half way home.

    Any ideas?

    2008 Chevy Silverado 1500 LT2 5.3 4x4

  2. #2
    stephan's Avatar
    Join Date
    Sep 2010
    Far West, Oregon USA,
    Blog Entries


    If your alternator is grounded properly, then this is most likely a bad chassis or body ground, or could be a bad connection in the main charging wire btw the alt & battery positive.
    1988 Chevy C-3500 2wd (no pic)
    350 c.i. 5.7 L Stock Block, 4 Bolt Mains
    L-31 Vortec Heads, Edelbrock Cam & Intake,
    Holley 650, Flowtech Headers, Magnaflow exh.
    Jet Trans 700R4, B&M Ratchet, 4:10 gears,
    3" susp. lift kit "shadetree"
    No rev limiter, No speed limiter lol

  3. #3


    hmm thats wierd tha happens on my new truck that has like 8000 miles
    "Silly Honda. My lug nuts take more torque than your car makes."

  4. #4

    Join Date
    Feb 2008
    Red Wing, Minnesota, United States


    Corrosion on any ground or power wire will cause a draw just like this, enough corrosion will even keep your car from starting. If you live an area with alot of salty, snowy, wet conditions or off roading/mudding this can be more common then you think. Start with what is free, check all the connections, make sure ALL the insualtion on the wires is intact and if you can take some readings, there could be a draw somewhere else that isnt strong enough to kill the battery. Eitherway your stock system as long as not modified should not be dimming or weakening during usage
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual

  5. #5


    x3. I'd locate the source of your problem would be somewhere around or having to do with your alternator.

    2006 Duramax LBZ
    Edge Evo
    4'' Diamond eye to 6'' tip
    16'' ion alloy, 33'' fierce attitudes
    Lots of work left to do!

  6. #6
    Jr. Apprentice
    Join Date
    Jan 2011
    Mukwonago, WI


    We'll it got really bad today. I got off early, cleaned up battery terminals, all ground connections I could find. The connections between battery, fusible link, alt wire and power wire seemed really bad, I was getting a lot of resistance across the fuse. cleaned everything up, took her for a test drive and it seems to be fine, so far. now onto my next issues!

    2008 Chevy Silverado 1500 LT2 5.3 4x4

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