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E46 - Hot Air From Vents - Water Control Valve??

dopper
in BMW 3 Series Forum

Featured Replies

Hey Guys,

Having issues with my air conditioning system always outputting heat (particularly hot in the footwell and front screen) no matter what "dot" the air diffusion system is on.

With the AC on it seems to cool a little through the middle vents but the footwell and front screen are hot, really hot.

Im thinking that perhaps the water control valve has got stuck open and is trying to offset the heat from the engine coolant back into the cabin?

What do you reckon?

  • Quote

    Very possible...

    I think maybe the airflow flap control is faulty/disconnected or even the infamous "Hedgehog" resistor !!!

  • Quote

    I think between you two its been diagnosed mate

  • Quote
    • Like 1

    I think between you two its been diagnosed mate

    Yup.

    Duo-Valve may not be regulating the flow to the matrix properly. Shouuuuuld be able to test with a multimeter as it is connected to the car via a 2-pin connector.

    Daz

  • Quote
    • Author

    Thanks for the replies!

    By Hedgehog do you mean the fan final stage resistor? Presumably this controls the fan speed only? If so I don't think it would be that as the fans ramp up and down as they should. Its just that once the car (coolant) is up to temp there is no way of getting ambient or AC cooled temperature air through the vents.

    Would you happen to know where the air flap control is located? How can i get access to it / check that its working correctly?

    Apologies for more questions :)

  • Quote

    I'd go with the water valves as I had the exact same problem with my E38 & replacement cured it. :)

    One of them will have failed in the open position.

  • Quote

    Thanks for the replies!

    By Hedgehog do you mean the fan final stage resistor? Presumably this controls the fan speed only? If so I don't think it would be that as the fans ramp up and down as they should. Its just that once the car (coolant) is up to temp there is no way of getting ambient or AC cooled temperature air through the vents.

    Would you happen to know where the air flap control is located? How can i get access to it / check that its working correctly?

    Apologies for more questions :)

    You'd be surprised what that annoying thing affects !!

  • Quote

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