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A6 climate control issues...!

Discussion in 'A6/S6/Allroad forum (C5 Chassis)' started by vr6it, Apr 14, 2008.

  1. vr6it
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    vr6it New Member

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    [Apr 14, 2008]
    Hi all,

    I was wondering if you can help, I've had my 01 2.5 TDI for a year and a half now and its perfect. However recently the climate has been acting a bit weird.

    Normal I set to manual and have the temp at 22 (warm) 23 (warmer) 24/25 (hot) for heat.... the other week it was cold air coming through at 24, now I have to turn it up to 29/30/HI to get hot air (its as hot as normal there though). Then if i put it to 28 its cold again!

    Any ideas? Anyone seen this before. I'm thinking its an electrical thing as I still get full heat coming through.

    Thanks in advance.
    Chris
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  2. SiliconS
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    SiliconS Member

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    [Apr 15, 2008]
    It's a climate control system, so if the interior of the car is warmer than the temperature you choose, you'll get cold air coming through until the interior cools down to the temperature set.

    Thus, if the interior was at 28 degrees and you choose 24 on the controls, you'll get cold air coming through until the interior cools down to 24 degrees.

    Does that help?
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  3. vr6it
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    vr6it New Member

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    [Apr 15, 2008]
    hi thanks for the reply.

    I use the system on Manual (Auto LED not lit) so the temp displayed is the temp of the air. Also when I do set it to AUTO its freezing in the car so at 24 it should be adding in hot air to heat the car up.

    Ta
    Chris
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  4. SiliconS
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    SiliconS Member

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    [Apr 15, 2008]
    We may have different systems then. I've got the climate control system with two digital displays for temperature.

    The owner's manual for my '99 A6 says:
    "The desired interior temperature can be preselected within a range from 18C to 29C. In the two extreme settings LO and HI the system operates continuously with maximum cooling or heating output; the temperature is not regulated automatically."

    I understand that to mean that whether Auto is selected or not, the temperature settings control the interior temperature of the cabin and not the temperature of the air coming into the car. The system will still cool or heat the air depending on whether the interior temp is higher or lower than the temperature you set in the dashboard unit. The only time this doesn't apply is when you choose LO or HI, in which case the air will always be cooled or heated regardless of the cabin's interior temperature.
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  5. maxlbrown
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    maxlbrown Deep Blue

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    [Apr 16, 2008]
    On the C5 full climate is not engaged in econ mode.
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  6. vr6it
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    vr6it New Member

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    [Apr 17, 2008]
    OK get what you mean about regardless of being on auto its still the cabin temp, I've had the car a year now and in that time if I set both temps to 23 its warm all the time and 24/25 its pretty hot. All of a sudden is freezing at those temp settings and I have to be up at 29 before I get any heat... something weird going on somewhere

    Also I do have it on econ pretty much all the time unless its summer.

    Nothing has really changed on the car, this only happnened after I hoovered it out and washed it!

    If there is still hot air coming out (at 29/HI) then I was thinking it cant be a airlock or the heater matrix as its still really hot. I'm leaning towards the climate control unit being at fault... however I still have heat so I wont be in a hurry to swap it out!
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  7. SiliconS
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    SiliconS Member

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    [Apr 17, 2008]
    You may have a problem with a temperature sensor then. If the system isn't getting an accurate signal about the temperature within the cabin then it'll go batshit trying to regulate the temperature. The climate control unit has a small grille about 2cm x 1.5 cm near the buttons and behind this grille is a small fan and a temperature sensor. The fan draws cabin air into through the grille and onto the sensor and this tells the system how close the cabin temp is to the temp you've set on the controls.

    If that sensor or fan has failed then you could have problems.

    Does the outside temperature sensor work OK? I had that fail on a Mercedes and that screwed up the AC's brain too.
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  8. vr6it
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    vr6it New Member

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    [Apr 23, 2008]
    I think you might be onto something there as it changed after I cleaned the car, now I dusted the inside (had a couple of months worth of build up as I just haven't had time to clean it) and hoovered everything. Maybe it got blocked? I'll have a look this weekend and report back! Thanks again
    #8

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