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Morimoto H4 Relay Harness - Weird delay when turning off??

Discussion in 'Lighting' started by ThunderOne, Mar 3, 2020.

  1. Mar 3, 2020 at 2:35 PM
    #1
    ThunderOne

    ThunderOne [OP] Well-Known Member

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    I've noticed a slight delay with my new Morimoto h4 bixenon harness which replaced my old crappy harness that was 10 years old.

    When I turn the headlight switch to "off", the lights take about a half second to actually turn off. Old harness = instant.

    The passenger side headlight turns off slower than the driver side. Old harness = both turned off at the same time. My guess for this one is, for some reason they wanted to use a separate ground for the passenger side ballast, and this is not allowing the headlights to turn off together.

    Turning on behavior is fine though.

    What gives? :notsure:

    Will try to get a video tonight to explain.

    video, and I was wrong, the pass side turns off first.
    https://youtu.be/0xnekcWBDSI
     
    Last edited: Mar 4, 2020
  2. Mar 3, 2020 at 9:23 PM
    #2
    ThunderOne

    ThunderOne [OP] Well-Known Member

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    Video added.
     
  3. Mar 3, 2020 at 9:31 PM
    #3
    tacoma_ca

    tacoma_ca Well-Known Member

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    I think this is to prevent brief interruptions of power from restarting the bulbs each time. E.g. some cars briefly switch off the low beam when high beam stalk is pulled, and the 1/2 sec delay would filter this out, improving bulb and even igniter lifetime. Usually this is timed by putting a capacitor across each relay coil. Could be a bad solder joint on one of the caps or a bad or different but still in spec cap on one of the relays. My Morimoto harness has about a 1/2 sec delay also.

    The bulbs pull a lot of power, more than could be stored in the ballasts via big caps etc. so the delay comes from the harness. A replacement relay module should fix it if tearing it apart doesn’t find the prob.

    I don’t think this is a bad ground issue but you can check by tying the two ground bolts together with a jumper cable.
     
    Last edited: Mar 3, 2020
  4. Mar 4, 2020 at 8:09 AM
    #4
    ThunderOne

    ThunderOne [OP] Well-Known Member

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    That's so weird, my old harness didn't switch off at all when switching from high beam to low beam, and the lights would turn off in sync and instantly when I turned off the headlights. Maybe this design is technically better as it draws consistent power with the "on purpose" delay? My old harness may have had a brief power drop from high beam to low beam, even though I couldn't see it with my own eyes. :notsure:
     
  5. Mar 4, 2020 at 9:30 AM
    #5
    ThunderOne

    ThunderOne [OP] Well-Known Member

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  6. Mar 25, 2020 at 4:04 AM
    #6
    TRSAndrew

    TRSAndrew Well-Known Member Vendor

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    Sorry for the delay--I have been so dedicated to building out our catalog for a total of 7 new websites.

    The delay is intentional--this is what keeps the lights on when you go between low/high beam without cutting off. MotoControl harnesses all do this.
     
    ThunderOne [OP] likes this.

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