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knock sounds when switch on/off heating 【A4 B7 1.9TDI】

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by Rock, Jan 18, 2012.

  1. Rock
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    Rock New Member

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    [Jan 18, 2012]
    hi everyone. My car recently having few knock sounds every time i switch on/off the heating. Anyone can give some advice what's that? thanks in advance
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  3. sidibear
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    sidibear Looking for Zombies !! Staff Member Moderator

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    [Jan 19, 2012]
    Maybe the flap closing, try it in E mode. Does it only do it when the recircluating button is on?
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  4. Rock
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    Rock New Member

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    [Jan 19, 2012]
    the sounds happens :

    every time i turn on/off the key, i mean give the power to the car electric device,but not turn on the engine. doesn't matter the heating is on or off.
    every time i turn on/off the recircluating button
    every time i switch on/off the heating, i mean the "OFF" button.

    but the the knock sounds from "turn on" is different from the sounds from "turn off". sounds like something knocked from two different way.
    #3
  5. PetrolDave
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    PetrolDave Well-Known Member

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    [Jan 19, 2012]
    If the knock is coming from under the dash it could be one of the air distribution flaps sticking - I had this a few months ago and was able to diagnose which motor using VCDS (VAG-COM). On investigation I found that the motor was OK but the operating lever had jammed.
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  6. Rock
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    Rock New Member

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    [Jan 20, 2012]
    was on motoway this morning, and it's raining. so i've also found i could hear the same noices as soon i use liquid screen wash, and every time
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  7. Rock
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    Rock New Member

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    [Jan 20, 2012]
    thanks for the experience.but is there anything should be replaced in this case?
    Last edited: Jan 20, 2012
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  8. Rock
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    Rock New Member

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    [Jan 20, 2012]
    E mode doens't make any different,but no noices from switch on/off the E mode
    Last edited: Jan 20, 2012
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  9. V6 Quatt
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    V6 Quatt Active Member

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    [Feb 1, 2012]
    Dave,

    how did you cure this what methods were used to un jam!!!!! as mine doing the same and wont de -mist windscreen help!! Vag says flapp jamed....

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  10. Rock
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    Rock New Member

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    [Feb 11, 2012]
    Problem found with the air recirculation motor, My part number is : 8E2.820.511D. Made in Spain

    i can't find the exactly same one on ebay. will phone the dealer on Monday
    Last edited: Feb 11, 2012
    #9
  11. sidibear
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    sidibear Looking for Zombies !! Staff Member Moderator

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    [Feb 15, 2012]
    Ahem, cough.
    :icon_thumright:
    #10
  12. PetrolDave
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    PetrolDave Well-Known Member

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    [Feb 15, 2012]
    Removed the motor (3 screws IIRC) and separated it from the mechanism which I checked was free to move by hand and then refitted the motor to the mechanism. That's all I had to do.
    #11

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