I am having problems with the haeater and a/c control in my 1985 300D. Fan/blower will stop or only start when ignition key is in on position before starting. Fan will stop sometimes after starting. Only have heat when engine is at low RPM, as engine RPM increases tempdrops. Any suggestions?

Pilot

 

I'm having the same problem with my 1981 300D. The fan only works when the key is turned one click to the right. When the car is turned on the fan goes off. Did you manage to fix your problem. Thanks