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Air Con wont turn ON !

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Rays18, Oct 15, 2012.

  1. Rays18
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    Rays18 East Tattoo

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    Ok so this has happened the past couple of days.
    Start the car turn on heating (doesnt matter what temp) the air con stays on the duration of the drive to work around 20 mins. You press the air con button but it doesnt go off. Go to work, have lunch around 3/4 hours later. Air con button will now work as it should.

    Any ideas?
    #1
  2. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    What do you mean it doesn't go off?

    If the ECON light is ON the AC is OFF.

    Are you saying that by pressing the ECON button to turn the AC off the light won't come on?
    #2
  3. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep

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    Even with the ECON on or off it should still heat up to set temp
    my econ is always off so AC on and i get red hot heat at high temp setting.
    your stat may be sticking open.
    #3
  4. Rays18
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    Rays18 East Tattoo

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    Sorry I got a bit mixed up with my words.
    The light will stay on (red) and when you press it will still be red.
    You can only choose to turn it on or off after a few hours. :S
    #4
  5. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    If the ECON light stays on that indicates the compressor isn't actuating, hence the AC isn't working.
    #5
  6. AlexGSi2000
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    AlexGSi2000 Well-Known Member

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    Has the weather been cold there for the past few days?
    Reason being is that I believe the Air-con wont turn on if the ambient temperature outside is low (cant remember what the temperature threshold is)
    If you try on your lunch - maybe the temperature has warmed up a few degrees outside?

    If the red ECON light is on then it means Air-Con is off "economy" - if the ECON light is off then aircon is on.
    #6
  7. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    It's 5C from memory. Either way, the ECON light should remain off.
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  8. Rays18
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    Rays18 East Tattoo

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    I guess its down to the cold months coming in.
    It only started like I said a few days ago.
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  9. mrxireland
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    mrxireland New Member

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    Are yous 100% sure on this because anytime my aircon was off, my light was off. I clearly remember anytime i wanted to turn it on, hit the button, red light came on and really cool air blew out of my vents.

    Im having same problem with my aircon, my red light is constantly on and i can hear the AC on when i stop with the engine on. I was thinking the mechanic balls my AC up after putting a 2nd hand head into my car.

    OP, when you turn the reds on your car, does your AC red light not go on even when you turn heating on. If so, this is what mines is doing and when i start car, the red light comes on.
    #9
  10. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep

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    not sure if you know how the CC unit works on the A4
    but you can have a/c on low then turn heat up and you will get heat
    as alex said above econ light on ac off
    econ light off ac on
    but you will get full heat with econ light on or off.
    #10
  11. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep

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    ]

    you either need a regas or a sensor get it on vcds and get codes
    tou have a head fitted the mech could have removed the ac pipe and lost the gas
    #11
  12. mrxireland
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    mrxireland New Member

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    Im now really confused because i honestly thought my aircon was constantly on because i couldnt turn this light off. With this thread now im scratching my head. So yous are telling me that ive always been driving with my air con on because my red light was always off. Another reason thou why i was thinking it was constantly on after i got my car back was that it was eating the petrol more so now than before i gave it to him.
    #12
  13. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    econ light on = no aircon
    econ light off = comperssor on and aircon on, consuming fuel, but drying the air and keeping the windows clear.

    Aircon will not turn on if the temp is around 5 degrees or below, needs a regas, or has a faulty component.
    #13
  14. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    Round and round and round and round and round ......
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  15. Rays18
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    Rays18 East Tattoo

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    So confused hahaaa.
    I was told when I bought the car the air con was on unless you press econ button thus turning red light on.
    But after a few days I thought it was the other way round as you could hear the air con motor switching/turning on.

    God I dont know now.
    #15
  16. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    We know!

    THAT is correct.
    #16
  17. pauldazzle
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    pauldazzle Member

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    Econ red light on = AC is off
    Auto red lights on & Econ light off = AC on
    Off switch red light on = Econ + AC are both off.
    #17
  18. mrxireland
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    mrxireland New Member

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    Why did audi have to go and do a thing like this,lol. Anyone with common sense would think that if you wanted something on, you press the button and the light would come on to tell you that what ever is is you wanted on, is on. Ive been driving my car with the aircon on everytime ive been driving it because i always had my light off. I never felt the cool air thou but as you say above, i musting have had auto on aswell. Im wondering now why my car is burning so much petrol now because i honestly thought it was the AC doing it.
    #18
  19. Ian-83
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    Ian-83 Member

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    I got a suggestion here................do the un-bloke thing! Read the manual for the car. Explains how it all works. :thumbsup:

    If the ECON light stays on all the time then it's a fault in the system. You should be able to operated it on and off even below 5 Celsius the only difference is the car see's the outside temp and won't run the AC compressor if it's below 5 Celsius regardless how you push the button as it over rides the system till the outside temp warms up.
    #19
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  20. Ian-83
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    Ian-83 Member

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    You don't have to have Auto turned on to have the Air con on. All auto on means is the AC control unit controls fan speed and air direction flow to maintain the temp you set on the AC unit.

    If you manually set full fan speed at feet at "low" setting the AC will be on blowing cold air at your feet. Push auto and it regulates the temp in the car by air direction and fan speed.
    #20
  21. Ian-83
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    Ian-83 Member

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    Audi did it so you drive around with the AC always working which lubricates the compressor and seals of the system so the AC system won't leak as much as if you constantly don't use the AC. Then when the hot sun comes out you find the AC has leaked the gas and doesn't work!

    AC should also be serviced every 2 years regardless if it still works or not as due to the pipes and seals being rubber they naturally breathe over time and slowly gas escapes reducing the efficiency of the system.
    #21
  22. mrxireland
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    mrxireland New Member

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    Well i must have a fault because when i press the econ button, the light is always on uless i keep my finger on it and even at that, when i keep my finger on teh button for about 30secs, the red light comes back on. Can you tell me what kind of faults would cause this light to be constantly on.
    #22
  23. Ste_Nova
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    Ste_Nova Active Member

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    just leave it in auto all the time, only touch the temp
    #23
  24. Ian-83
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    Ian-83 Member

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    You can have several faults but could be a faulty pressure sensor, no gas in the system or a fault with the AC compressor.
    #24
  25. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep

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    god its still here
    #25
  26. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    I've not known anyone get quite so confused about it before!

    ECON means 'economy mode'. When economy mode is on, the light is on. Simple.

    If you need to hold the button down to stay in economy mode, then as mentioned you have a fault. I suspect with the timeout symptom you mentioned its probably just low on gas, but its easy enough to get it tested.

    I never turn my aircon off, the whole HVAC system was designed to have it on all the time, and its much more efficient to do so. If I was worried about economy I wouldn't have bought a 6 cylinder quattro car.
    #26
  27. pauldazzle
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    pauldazzle Member

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    Regas gets my vote!:banghead:
    #27
  28. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep

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    close thred gets my vote !
    #28

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