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1984 400i headlight problem

Discussion in '365 GT4 2+2/400/412' started by oldcoin, Apr 24, 2020.

  1. oldcoin

    oldcoin Formula Junior

    May 1, 2006
    251
    Reno NV
    Full Name:
    Tony Mitchell
    1984 400i 22,000 miles, always garaged.

    Yesterday, I changed the oil after the car has been sitting for a little too long. Went for a drive and everything was great.

    When I got back to the garage, I noticed that both headlights were "up" about 1/4 inch. When I start turning the knob on top of each motor, they suddenly open full under their own power with no headlight on and then fully close themselves. They do not cycle repeatedly.

    Lights were working perfectly the last time I was driving at night, but I don't really know how long ago that was. The car has not been washed. The light control stalk feels right.

    I find no fault with fuses or relays. What an I looking for? Any help appreciated.

    Tony
     
  2. raemin

    raemin Formula Junior

    Jan 16, 2007
    378
    Lyon (FR)
    Full Name:
    R. Emin
    Check for moisture in the 4 pins connector that is hidden in the left fender (close the the lifting motor). Do the same with the other connector on the right fender.

    Check for mechanical failure: if you disconnect both connectors, you can manually operate the lifting motors. There is a knob on top of the rubber boot that protects the electric motor. This knob is roughly the size of a coin. You can turn the two knob until both headlights are up. The headlights are heavy, so this tasks requires a bit of force, but excessive force would mean there is a mechanical failure.

    If the gears of the motors are not damaged, you may have to open the mechanisms and check for electrical gremlins : two mechanical switches and two diodes are used to reverse operation and send feedback to the dashboard. Some users on this forum have had diode failures.
     
  3. oldcoin

    oldcoin Formula Junior

    May 1, 2006
    251
    Reno NV
    Full Name:
    Tony Mitchell
  4. Jasonberkeley

    Jasonberkeley Formula 3
    Silver Subscribed

    Apr 23, 2017
    1,074
    New York, NY
    Full Name:
    Jason Berkeley

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