W203 heater blows cold

[Ronmac]

Can anyone out there help.
My C200 cdi heater only blows cold air unless I turn the controls fully up it then blows really warm. I cannot get anything in between.
The engine temp sits about 80 deg.which I think is normal but the warm air only comes out when controls maxed out.

 

[sspeed]

Can anyone out there help.
My C200 cdi heater only blows cold air unless I turn the controls fully up it then blows really warm. I cannot get anything in between.
The engine temp sits about 80 deg.which I think is normal but the warm air only comes out when controls maxed out.

I have to say the heater controls on my C270 Cdi (facelift) leave a lot to be desired....
Very inaccurate especially on auto..
Have you tried resetting the flaps ??

203

To reset heater flaps and actuators

Switch on ignition.

Press recirculated air and defrost buttons on control panel together for longer than 5 seconds.

The LED's in the defrost and recirculated air buttons flash alternately.

Wait until the LED's stop flashing (approx 30 sec) system set to defrost LED on.

Switch off ignition.

After 40 sec re start engine.

 

[Ronmac]

I have tried resetting the falps this does not make any difference.Air seems to blow out of the correct places but not warm at all unless maxed out any other setting blows cold.

 

[jim47]

my w209 has same problem did you find a fix?

 

[Ronmac]

I change the external temp sensor on the front bumper and my heater temp seems to work OK. According to other threads on this site it has nothing to do with it but it worked for me. The temp sensor was reading high i.e. 5 degrees C would read about 40. Hope this helps