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2010 Gen III Driver's side headlight and foglight both stopped working

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by SonicSleuth, Aug 3, 2022.

  1. SonicSleuth

    SonicSleuth New Member

    Joined:
    Aug 3, 2022
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    Location:
    Cleveland, OH
    Vehicle:
    2010 Prius
    Model:
    III
    Problem as in in the title... 2010 Gen III Driver's side headlight and foglight both stopped working. All stock equipment. Initially I thought it was just a burned out headlight bulb, so I bought a replacement, no good. So I popped out the passenger headlight, swapped bulbs... the new one worked in the passenger side, the (working) passenger bulb didn't work on the driver's side. At some point I realized the foglight (high beams? If that's the right terminology) on the driver's side was *also* not working, so I assumed it was an electrical fault. I had recently had a fuse go out (12v light fuse) so I replaced that and checked all my other fuses, they all seemed okay.

    So, then I yanked out my multimeter to see if I was had current on my headlight housing, and I don't think there is... but I'm also not an electrician, so I'm not sure I'm measuring it properly.

    At this point I'm asking... does the wire harness for the headlight also supply power for the foglight AND the turn signal lamp? Because my turn signal lamp is working fine on the driver's side, so if they're all on the same harness, it's probably NOT a harness issue? I've heard of problems with the relay, but I don't really know what that means in the grand scheme of things.

    Might it be a ballast replacement? I don't think the ballast also feeds the foglight, does it? If it does, apologize for my ignorace here.

    Also, if it's possible it's just a fuse thing and maybe I missed a bad fuse, let me know. But I don't think it's fuses, since the passenger's side works fine. Seems unlikely they have the fuses broken down that way.
    I would love any helpful ideas. Even some unhelpful ones.
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base