Mercedes w204 fan on constanly

[coolboy2015]

I have a Mercedes c20cdi on 2008 reg, the issue is that the fan kicks in as soon as you start the car. Any advice would be appreciated.

Also any recommendations to take the car to get it diagnosed, my location is Rochdale.

 

[MancMike]

Your A/C is on?

The fan is needed for A/C to work otherwise, while stationary, there'd be no air going through the condenser.

 

[coolboy2015]

I've tried with ac on and off, it makes no difference .

 

[mersum1es]

Check ALL fuses, undervoltage of ECU will cause it. Second, it may be fan control unit failing. Then Rarely malfunction of AC sensor or engine temp sensor...

 

[C180CGI]

Same problem happened to me on multiple occasions on a VW Golf. You will get the engine light come on after driving it a good 100 miles ish and you need to replace the temperature sensor. Was cheap on Golf £30 and was not charged for labour since it took the mechanic 2 minuites.

 

[coolboy2015]

Managed to get it fixed the aircon pressure sensor was replaced and all seems well.

 

[Iqbal7]

Managed to get it fixed the aircon pressure sensor was replaced and all seems well.

Hi, I have the same problem. Just wondering how much it cost to renew the air-con pressure sensor and if you could reccomend a mechanic. I would prefer to avoid the main dealer if I can.

 

[OneForTheRoad]

Hi, I have the same problem. Just wondering how much it cost to renew the air-con pressure sensor and if you could reccomend a mechanic. I would prefer to avoid the main dealer if I can.

the switch itself range from £30 to £40 , afaik it sits on top of a tyre type valve ( schraeder ), so no gas it lost when you change it.

 

[Iqbal7]

Thanks for the prompt response. Have you changed this yourself or did you use a mechanic ? Don’t suppose you happen to know if any codes need resetting after installation. Lastly, Is there any way of confirming the faulty sensor on a diagnostic machine, if so, could you reccomend one for purchase.

 

[OneForTheRoad]

icarsoft mb2 talks to the aircon . the switch simply screws out using something like a 19mm spanner