07 Tahoe headlight/alternator issue

Discussion in 'GM Electrical Tech' started by TonyO51165, Mar 19, 2017.

  1. TonyO51165

    TonyO51165 New Member

    In need of some help please....I have an '07 Tahoe with headlight issues. Bare with me as I try and explain this the best I can....When I start the truck the headlights don 't come on when the switch is on auto. When I turn the switch to on, they still don't always come on. I have to turn the switch on/off several times, or barely turn the switch and they will finally come on. I thought it was the switch, changed it, but still the same. I've also just noticed that if I turn the lights off, the alternator won't charge. However, if I leave the switch on auto or have the lights on, the alternator charges just fine. I'm thinking a possible ground problem somewhere? I've checked fuses and they are ok...not sure how to check relays. Another thing I have noticed is, when I'm sitting in the truck without it being on or even having the key in the ignition, every once in a while I hear a click sound coming from around the door lock buttons on the arm rests. If I'm missing any pertinent information that might help, please ask and I'll try to describe or explain what ever I might be missing. Thank you in advance, I hope I'm able to get some help on this.........
     
  2. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Have you hooked a diagnostic tool up yet and checked for any fault codes?
    Something many owners of newer vehicles are not aware of is the fact that these newer vehicles will give codes for issues but not give a CEL making you aware of a problem.
    Unfortunately your headlights, by route of an extensive wireing system connect to the BCM, Body Control Module, and then go out to the individual lights. Not saying it's the problem, just saying it's another item to check.
     
  3. TonyO51165

    TonyO51165 New Member

    No I haven't, I wasn't aware that it would give me anything. When I get to work tomorrow I will have our mech. hook his up and see if he can get anything. Thanks for the advice, I'll keep you posted.
     

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