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Left side headlight plus fog light stopped working

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Lycanthropic, Jan 4, 2024.

  1. Lycanthropic

    Lycanthropic New Member

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    My entire left front lighting structure stopped working. Just moved from LA, always with a garage (since I drove new off the dealer lot), to wet and cold New England with no covered parking. I've been up here for about 3 months, and now the fog light and headlight (both dim and bright) of my HID left side has stopped working. I took the assembly out and noticed that there was condensation, so I dried it out with a fan for half a day, re-installed, and still nothing. I checked the smaller fuses for the left headlight and they were fine.

    My thoughts are:
    1. The ballast is blown? It looks fine, but since it's incased in epoxy, I can't see the actual circuitry, but I did remove it and check as much as I could for any scorch marks or burnt smells...nothing there.
    2. There are larger relays for the headlights, but I'm not skilled with a multimeter (although I do have one). Might they cause this issue?
    3. I assume it's not the bulbs, since all stopped at the same time.

    I was thinking of ordering a new ballast and replacing it, or perhaps starting with new relays. I might get a new housing as well, as I think I found the leak area and it's due to me replacing the bulbs over the years and snapping off the tabs on the large circular cover you rotate to access the HID (wasn't tight anymore).

    I prefer not to take it into the dealership if possible. I would appreciate any insight.
     
    #1 Lycanthropic, Jan 4, 2024
    Last edited by a moderator: Jan 4, 2024
  2. Tombukt2

    Tombukt2 Senior Member

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    So on the side where everything is burnt out that means the little Amber marker light that's only a 194 regular bulb and has nothing to do with the HID system is also out Is this correct? Then I wouldn't be diagnosing a ballast just yet so it seems the hold right or left side whichever we're talking about here is completely out The fog light is not even well it is related but anyway and it is out too so the headlight fog light and the marker light the 194 are all non-working and you already have the headlight out well that's kind of cool so you can check the plug that goes to that little orange marker light put the headlight switch on the first position Do you measure voltage at that plug for the little 194 marker?? I think not so you're working back from there
     
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  3. Lycanthropic

    Lycanthropic New Member

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    Thank you for the reply. Where is the little amber marker light located? Do you mean as part of the headlight assembly, or somewhere else? I know every light on the front left is out, for sure.
     
  4. Lycanthropic

    Lycanthropic New Member

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    Thank you for the reply. Where is the little amber marker light located? Do you mean as part of the headlight assembly, or somewhere else? I know every light on the front left is out, for sure.
     
  5. Tombukt2

    Tombukt2 Senior Member

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    Yes the amberfront marker light that's in the upper portion of your headlight assembly so if everything on the left side is out you need to be looking at that left side circuit where it crosses over runs across the front bumper I believe or just behind it however you look at it and all that there's also left and right hand fuses I do believe for the headlights right under until the left of where the pull is for the hood.
     
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  6. Lycanthropic

    Lycanthropic New Member

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    OK, I'll check it first thing tomorrow. Yes, all the lights in the left front headlight assembly are not working. So, just to be clear (as I'm a little confused here), I'm looking for a wire (what you're calling circuit) to make sure it's connected? I did check the regular fuses, and they're all good (the ones in the engine compartment). I can't check the relays, as I'm not sure how to know if they're bad or not.
     
  7. rjparker

    rjparker Tu Humilde Sirviente

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    I would check for a ground cable to chassis or a ground junction connection problem in that area.

     
    #7 rjparker, Jan 5, 2024
    Last edited: Jan 5, 2024
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  8. Lycanthropic

    Lycanthropic New Member

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    Great, thanks. I'll check that schematic and then check the area today.
     
  9. Tombukt2

    Tombukt2 Senior Member

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    If you look along the frame rail that the fender mounts to but under the hood part of the frame rail area you'll see some big white wires with black lines on them three or four of them connected to a big spade looking terminal factory crimped and made for a 10 mm bolt headed bolt to go through so that makes it a 6 mm thread I think and they both right there maybe on either side of the car I have to go out and look but it would be about brake reservoir level height or just under the brake reservoir but on the frame rail of the car not the firewall the frame rail I would be shocked and listen engine's been pulled or something's going on serious as far as repair wise these things would almost be impossible to be messed with they are bolted down they came that way from the factory usually people don't touch them they add their own grounds for nonsense they're installing and they never touch these but it certainly worth a look everything's going to have to be looked at because apparently you have a whole side of the car out when this happened to our 13 My wife had dinged the front end of the bumper cover just under the headlight she hit a piece of metal that piece of metal pushed the front bumper cover into some wiring that runs right underneath the headlight but did not damage the headlight It's slightly bent the front apron metal behind the headlight near the core support and slice the wire that made the turn signal on the right side not work and I think maybe the marker light was messed up but the headlight worked so similar problem but not exact I literally took my multi-tool and sliced a very small square in the bumper cover so I could reach the wire make a splice and then literally glue with urethane glue that square I cut out of my red bumper cover You can almost not see it That's because this is a car that's being phased out and we didn't want to spend the labor at time taking the bumper cover off and doing the proper repair this car is going to the trash ASAP as soon as it can explode and blow up.
     
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  10. rjparker

    rjparker Tu Humilde Sirviente

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    The right way is with a meter and a 12v Automotive Power Circuit Tester. Easy with a schematic and experience, so sometimes the right tool and guy makes repair simple.

    Assuming this is the circuit on your car, I would verify 12v on the pink and a good ground on the w/bk with the lights on.

    IMG_3848.jpeg

    The orange controls high or low beam
     
    #10 rjparker, Jan 6, 2024
    Last edited: Jan 6, 2024
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  11. rjparker

    rjparker Tu Humilde Sirviente

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  12. Lycanthropic

    Lycanthropic New Member

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    That makes total sense! I had a small fender bender a few weeks ago with my front bumper. No damage, but I'm sure it flexed the bumper in. Thank you for the detailed info and back story. I'll try to check tomorrow, but we have a blizzard moving in tonight, so I'm not sure if I'll be able to check it in the next few days. Fortunately I don't have to drive (can get a ride in to work) next week.
     
  13. Lycanthropic

    Lycanthropic New Member

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