Driver low beam not working

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by redprius10, Dec 16, 2024.

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  1. redprius10

    redprius10 New Member

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    Hi folks....need some help. Driver low beam not working. It's not the bulb. Bought a new bulb (Syvania 9005). No go. Swapped with working passenger side bulb. No go. All other lights on both sides work, including high beams on problem side.

    I tried to test voltage at the connector, but getting very low reading so I'm probably not testing it correctly. I did measure resistance and got a reading of 1.4 ohms which I believe is normal.

    I didn't check anything in the fuse box since everything else tied to that 40A fuse is working.

    Not sure what to do next. Replace the headlight connector?

    Any guidance would be much appreciated. Thanks.
     
    #1 redprius10, Dec 16, 2024
  2. Tombukt2

    Tombukt2 Senior Member

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    H4 connector suspect . You measure voltage w ground on chassis and probe the three contacts in plug with lo beam on note hot term . Now hi beam on probe again note hot added .. low voltage switch maybe
     
    #2 Tombukt2, Dec 17, 2024
  3. Brian1954

    Brian1954 Senior Member

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    Let me point out to you that the 9005 bulb is for the high beams. You need an H11 bulb for the low beams.

    I know that this will not help you fix your problem, but I wanted to make the correction.
     
    #3 Brian1954, Dec 17, 2024
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  4. redprius10

    redprius10 New Member

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    My plug is a two wire plug....Violet and Black/White
     
    #4 redprius10, Dec 17, 2024
  5. Merkey

    Merkey Active Member

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    I was going to say the same. H11, not 9005.
     
    #5 Merkey, Dec 17, 2024
  6. redprius10

    redprius10 New Member

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    I only have a single bulb for high/low beams. It is a dual filament bulb.
     
    #6 redprius10, Dec 17, 2024
  7. Merkey

    Merkey Active Member

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    Must be unique to the four. My 2010 is a II with separate low and high bulbs.
     
    #7 Merkey, Dec 17, 2024
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  8. Brian1954

    Brian1954 Senior Member

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    The 9005 is a single filament bulb.

    Can you please upload a picture of your headlights and the bulb?
     
    #8 Brian1954, Dec 17, 2024
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  9. BiomedO1

    BiomedO1 Senior Member

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    If you place a known good bulb into the socket and it still doesn't work, It has to be the connector or wiring. NOT the fuse or switch, since that's common to both left and right side. It could be a relay, depending on how it's wired - but most OEM's use a low beam relay and a high beam relay to make things easier to troubleshoot. Your fuse cover usually has a map of fuse locations that'll give you a clue of how it's laid out, but you'll first need to figure out what bulb you need first and get the correct one!! You stated a 9005, clearly a single filament bulb. Attached is the two most likely candidates for an automotive duel filament bulb. They are obviously NOT interchangeable, unless you rewire your connector.

    Hope this helps....

    9007 vs. 9004: What's the Difference Anyway?
     
    #9 BiomedO1, Dec 17, 2024
    Last edited: Dec 17, 2024
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  10. ChapmanF

    ChapmanF Senior Member

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    Low beams in your 2010 are fed directly by the "integration relay", the long white box down the side of the fuse box, which also feeds a number of other things.
     
    #10 ChapmanF, Dec 17, 2024
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  11. xliderider

    xliderider Senior Member

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    You say you bought a new Sylvania 9005 bulb, that's a single filament bulb for the highbeam on a 2010 Toyota Prius.

    As noted, the low beam bulb is an H11 bulb.

    SM-G781V ?
     
    #11 xliderider, Dec 17, 2024
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  12. redprius10

    redprius10 New Member

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    Ok guys...maybe I'm an idiot. The circled light is the one that does not work when I turn the headlight switch on. It does work when I turn on the brights. The same 9005 bulb (see photo) was installed on both sides and the new one I bought is exactly the same bulb. I could have sworn, but now I'm doubting myself, that on the working passenger side, the circled light came on with light switch in regular position and went to bright when switched to bright.

    IMG_2333.jpeg IMG_2331 2.jpeg
     
    #12 redprius10, Dec 17, 2024
  13. Brian1954

    Brian1954 Senior Member

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    The circled light is the high beam. The light next to the circled light is the low beam (looks like a fish eye).
     
    #13 Brian1954, Dec 17, 2024
    Last edited: Dec 17, 2024
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  14. redprius10

    redprius10 New Member

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    Ok...I will confirm this evening when my daughter gets home with the car, but I think maybe I have a different issue than I thought. I think the passenger high beam turns on in the low beam switch position. I'll report back. Thanks for all the replies.
     
    #14 redprius10, Dec 17, 2024
  15. BiomedO1

    BiomedO1 Senior Member

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    Outer lamps ON in headlamp on position (low beams) green lamp indicator. Inner lamp on with signal stalk pushed forward, blue high beam indicator ON. You should probably re-read your operations manual.
     
    #15 BiomedO1, Dec 17, 2024
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  16. redprius10

    redprius10 New Member

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    I understand how the lights work. I believe the passenger high beam is coming on when the switch is in the low beam position, but need to confirm when my daughter gets home with the car.
     
    #16 redprius10, Dec 17, 2024
  17. rjparker

    rjparker Tu Humilde Sirviente

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    You are probably seeing a parking or running light

    IMG_6946.jpeg
     
    #17 rjparker, Dec 17, 2024
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  18. redprius10

    redprius10 New Member

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    Hmmm....daytime running light. Now that makes more sense. I assume that's a separate bulb?

    Edit: Did some reading....I don't think my car 2010 Prius IV has daytime running lights. Am I wrong?
     
    #18 redprius10, Dec 17, 2024
    Last edited: Dec 17, 2024
  19. BiomedO1

    BiomedO1 Senior Member

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    My 2012 Prius C had, off, DLR, parking, ON - depending on trim level, there may be an auto position.
    Canadian car DLR's were a requirement, I don't think they had the DLR option on their stalk.
     
    #19 BiomedO1, Dec 17, 2024
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  20. BiomedO1

    BiomedO1 Senior Member

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    Sorry, It doesn't seem like you know how the lights work, their position, operations, nor bulb configuration. :censored:
     
    #20 BiomedO1, Dec 17, 2024
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