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Electrical issues

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Hangn69, Feb 1, 2010.

  1. Hangn69
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    Hangn69 New Member

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    [Feb 1, 2010]
    Having strange issues with my 04 avant last couple of days.Everytime I switch my headlights off the tailgate opens.If I press the lock button next to the drivers door handle before I do this it doesnt open the tailgate.Anyone have any ideas?
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  3. Woorlord
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    Woorlord shifting to Hyperspace... . VCDS Map User

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    [Feb 2, 2010]
    Strange combination of faults?

    "Power control unit" (PCU) deals with the headlights and the "Convenience module" (CM) deals with the locking/alarm etc., all interfaced to the door switch by CAN-BUS.

    PCU under steering wheel to lower right on RHD car.
    CM under front passenger seat.

    Does your remote open the tailgate OK?

    Perhaps a short in the loom between signals for tailgate lock and rear lights - may be worth tracking the loom and check for possible shorts or damaged wires?
    Looms should run under the internal plastic covers on top of sills - however would have thought lights and locking signals run on different sides owing to module locations.
    Therefore, one would assume possible wiring fault where the two wires merge together - maybe in the tailgate area - number plate lights and wire to lock motor probably close to each other??
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  4. Hangn69
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    Hangn69 New Member

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    [Feb 2, 2010]
    opens normally with remote ,works fine in every way.Just opens when I turn headlights off.I have replaced the lock mechanism recently as the microswitch inside was gone but it worked fine only the last couple of days its started acting up.
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  5. Hangn69
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    Hangn69 New Member

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    [Feb 7, 2010]
    update ,when I turn headlight switch off the lock actuator/rod is opening the tailgate, not the alarm/microswitch.Also while trying to solve this problem I have found that if I disconnect the harness plug from the back of the headlight/sidelight switch with it in the off position and turn the ignition to on but not start the headlights and side lights are all on,is this normal?
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  6. NHN
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    NHN Retrofitter - Audi - VW - Skoda - Seat Site Sponsor VCDS Map User

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    [Feb 7, 2010]
    Would seem to be correct from a safety view, as if it doesnt detect the switch, then its better to have them on at all times as it doesnt matter if there on during day & better safe than sorry if the headlight switch failed at night huh, probably a default feature
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  7. J7USS
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    J7USS Shuddup Foooool!!

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    [Feb 7, 2010]
    "Autobots Stand by"... :scared2:
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