GP964

Hello,

Everytime I shut off the car I hear what sounds like a fan buzzing in the A/C control area. It stays on several minutes after the car is off. Does anyone know what this is? What is it for?

Thanks
GP

Adrian

Dear GP,
You have heating selected correct. The sound is the temp sensor fan. It runs for up to 20 minutes after the ignition is turned off. The HVAC remains active for 20 minutes after ignition is turned off for engine overheat protection. Nothing to be worried about. Normally will not be heard if aircon is selected and the temp control **** is in the blue dot position.
Ciao,
Adrian
911C4

GP964

Thanks Adrian

johnfm

Yes, but it should only come on if the engine is particularly hot - if the fan stays on after a 5 minute drive, the temp sensor in the duct inside the engine bay is probably no good.

John Boggiano

John, I'm not sure, but it sounds to me like you mistook the reply - the little fan in the sensor area of the HVAC control unit will run-on whether the engine is hot or not, but the cooling fan at the engine will only trigger (during the 20 min 'active after shutdown' period) if the engine is very hot.

kylejohnston1

Time to resurrect on old thread!

I'm hearing a similar noise coming from the CCU, even after I pull they key out of the ignition. However, this is only when the a/c button is engaged. If I disengage the a/c button, the noise stops. I just had my evaporator replaced and my a/c is working for the first time since I bought the car so I'm not sure if this is normal or not?

kylejohnston1

Nevermind, the fan does turn itself off within several minutes after the ignition is turned off. I did some more searching and it sounds like this is normal.

The fan is a bit loud so I'm going to tackle this procedure soon and see if it helps:

https://rennlist.com/forums/964-foru...y-ccu-fan.html