The AC and heater on our 05 CLK320 smells very bad. It smells musty like the car has water under the dash in the AC. It only smells when you first turn it on after it has been sitting, after about 2 min the smell goes goes away. Could it be AC drains or some thing?
Change your cabin filter..........IT TOO OLD !!! Filter is on top of the battery inside the engine bay.:thumbsup: