Headlight symbol says headlights on - but no headlights on 2006 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jim2006Prius, Jul 29, 2014.

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  1. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Measure the voltage again at the relay socket, switched terminals. You should see 12VDC at only one of the two terminals when the relay is removed from the socket.

    Then short the relay switched terminals together at the socket and see if you can get the headlights to turn on. If they do not turn on, you need to investigate the DIM relay next.
     
    #21 Patrick Wong, Aug 21, 2014
  2. jim2006Prius

    jim2006Prius New Member

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    Patrick,

    There are a total of 4 sockets. Do I put a paper clip between the two socket terminals that are showing 12v power when I connect them to the multi-meter ? I want to make sure I am connecting the two proper sockets together.
     
    #22 jim2006Prius, Aug 22, 2014
  3. jim2006Prius

    jim2006Prius New Member

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    Patrick - I think we did it - or you did it. I went out to the car and connected a wire between the + and - sockets that was giving a 12 volt reading and the headlights went on when I had the headlight switch turned on. It was great to see the headlights work for a few seconds then I quickly removed the wire. I am also noticing a white spider web than I cleaned out of the positive socket had reappeared.
     
    #23 jim2006Prius, Aug 22, 2014
  4. xliderider

    xliderider Senior Member

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    I haven't read through the entire thread, but it sounds like you now need to get another relay.

    SCH-I535
     
    #24 xliderider, Aug 22, 2014
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Make sure the H-LP relay socket is clean. Then if you want, you can try to insert the H-LP relay once more to confirm it is the failed part.

    Or you can apply 12VDC to the relay coil terminals of the relay and then measure resistance across the switched terminals of the relay. If working correctly, it should measure 0.5 ohms or less after you account for resistance of the test leads.

    Given your prior success by shorting the switched terminals at the socket, you will probably find that the relay switched terminals show high resistance when you try this test. That would confirm that the H-LP relay needs to be replaced.

    My guess is that your local Toyota dealer will charge ~$75 for a new relay.
     
    #25 Patrick Wong, Aug 22, 2014
  6. jim2006Prius

    jim2006Prius New Member

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    I took a cotton swab and wiped down the sockets (not sure if there is something better to use)
    Inserted relay and still did not work. I called and it is $75 for the relay and will get next week.
    Will keep you posted
     
    #26 jim2006Prius, Aug 22, 2014
  7. jim2006Prius

    jim2006Prius New Member

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    I obtained two H-Relays and when I plug them in and the lights did not work.
    I went back and connected the + and - and the head lights go on, with a little squealing sound.
    I have to admit I bought the two relays through Ebay and I thought the odds were I would get a good
    one so is it I have 3 bad relays or is there something else wrong we should be looking at? The numbers
    on the relays match perfectly to the original.
     
    #27 jim2006Prius, Aug 28, 2014
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I've explained in earlier posts, #9 and #25, how to test the H-LP relay. My personal policy is to do my best not to repeat the same message more than once within a thread.

    Make sure when you are shorting across the relay socket, that you are shorting what would be the relay switched terminals.
     
    #28 Patrick Wong, Aug 28, 2014
    Last edited: Aug 28, 2014
  9. jim2006Prius

    jim2006Prius New Member

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    Ends up it's not the head light relay. Went to the Toyota Parts department and the parts person was very helpful.
    The parts guy checked the electrical and determined there were a couple of the same relays in the car so he helped me
    switch and plug in a working relay and still there were no head lights.
    Frustrated I decided to pay Toyota to do a 30 minute inspection, since they just saved me from having to spend $80 on a new relay
    I didn't need. The mechanic tested the relay inlet and stopped when he noticed there was no ground and said there would be no
    charge if I did not want to proceed, but figured it would take a couple hours to resolve. I decided it was time to let someone who works in this area try to solve this and I will update what the end result is.
     
    #29 jim2006Prius, Sep 15, 2014
  10. Chris Montague

    Chris Montague Junior Member

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    Jim -

    Not sure if you still follow this thread, but I'm interested in what the resolution was here....I may be facing something similar.
     
    #30 Chris Montague, Sep 29, 2015
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