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power locks not working ?!

Discussion in 'A4/S4 forum(B5 Chassis)' started by polskiaudi, Mar 28, 2009.

  1. polskiaudi
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    polskiaudi New Member

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    [Mar 28, 2009]
    after i had some work done on my 97 audi a4 1.8t the power locks dont work there is a loud humming noise coming from the back. does anyone know wat the problem is cuz i am gonna need gas soon and the gas tank door is locked:(
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  2. polskiaudi
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    polskiaudi New Member

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    [Mar 28, 2009]
    does anyone have a diagram that shows how the lock mecahnism works???
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  3. Siena
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    Siena Active Member

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    [Mar 28, 2009]
    The central locking works by means of a bi-pressure pump.
    Suction to open, and pressure to lock.

    The pump has a graphite impeller, and there are vacumn lines connecting the pump to the door actuators, trunk and fuel flap actuators. If any of these pipes split (usually where they pass through the drommets ito the doors) the pump will run on for a while.

    The graphite impeller is fragile, and will often crack. So the pump will work, but with no impeller, won't generate any pressure to lock the doors, or vacumn to unlock them.

    To open the fuel flap, you need to pull the trim inside the luggage compartment (driver's side) free from the body, and just before the area of the flap, you'll need to disengage the actuator from the inner frame, as in lower diagram:

    [​IMG]
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  4. Siena
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    Siena Active Member

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    [Mar 28, 2009]
    As you just had some work done on your car, it's possible a pipe was removed, and not replaced.

    What work did you have done? What area of the car was the work carried out in?
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  5. Siena
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    Siena Active Member

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    [Mar 28, 2009]
    If your pump is bust, I have a spare one.
    But first, you need to determine where your leak is (as I suspect there is one) and rectify it first.
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  6. polskiaudi
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    polskiaudi New Member

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    [Mar 28, 2009]
    thanks and the work was trans computer replacement.
    and other than between the doors where else should i look for a leak
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  7. Siena
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    Siena Active Member

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    [Mar 29, 2009]
    Besides between the doors, I'd look at the pump vacuum connections, and the connections on the trunk and fuel flap actuators.
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  8. polskiaudi
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    polskiaudi New Member

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    [Mar 30, 2009]
    i checked the acuators and no leaks so its the pump then.
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