I have a C-240 2004 that is running very well, except that on the left side (Driver side in my case) I have no ventilation and no heat at all ! The climate control compensate by sending twice more heat on the right side.
I did a few climate reset control by pressing simultaneously Defrost and Recycle button (5 sec), the led flash the stepper motors are doing there jobs, I have air temporally on left side but when the process ends the problem comes back, no air on left side !!
Does anyone have experienced this problem ? I would appreciate some hint to what is happening....

 

Hello, never had this problem myself, and dont know much about how it all works, but have you seen this thread?
https://mbworld.org/forums/c-class-w...flow-face.html

post #8 tells me you can get access... maybe then you could 'see' whats going on (look while you run the test mode.. and compare it to when its not working in normal mode) hopefully you see the problem

"The W203 climate unit is not a known weak spot. The stepper motor linkages that it controls are, at least pre-2004 and possibly pre-2005."

strange that it works in test mode

 

I suspect the climate control panel (the electronics), I have ordered on eBay an pre-owned unit, it should arrive in Canada between Dec 4 an d Jan 4..... Will see if it makes a difference.
Thanks for your reply. Regis

 

AH yes, if its working in test mode then its 'physically' fine.. well done diagnosing it, i didnt know you could replace the panel. I hope it fixes the problem.

Do you know how to replace one of these panels? im going to assume its not too different from this video

Actually it depends on your specific model because this video shows a more in depth removal process is needed (around 7:20 he removes it) looks like he has your model.. so get studying! lol

Maybe you dont have to remove all what he has... at 6:24 he removes the 2 screws that hold the faceplate... maybe the other steps are not needed for just replacing what you need to
Hope this helps