Hi !

I have the problem with heating. Passenger side is ok but driver side front and rear blows just cold air.
Dealer diagnose was that air mix sensor motor. They cheked the motor is ok .Who has some experience with it?

 

I had this issue and it's most likely a clogged heater core. The PO must have put some stop leak or something in there. Rather than paying for and changing the core which is a $1700 job at the dealer the tech flushed it twice and the heat came back but it blew cold again. So I went out and bought a transfer pump from harbor freight and some CLR after I watched a Youtube video of a guy flushing his VW Jetta core. I poured the CLR in the core and let it sit for about 45 minutes then got a bucket and filled it with CLR and flushed/back flushed the core repeatedly for hours. I just did it the second time last week and still got plenty of crud out. Hopefully this is not your issue.

I also changed the drivers side servo that controls the heat but that did not seem to which did not fix my issue. I have plenty of heat now.