The heater fan on this car seems to turn itself on and off, accompanied by a noticeable "click". I have already been sitting in the car listening to the radio with the key in the "acc" position and the "off" button pushed on the heater control and I hear a "click" and the fan turns on. Other times I have been driving down the road with the fan running even though the "off" button is pushed in then I hear a "click" and the fan turns off. Also the a/c compressor just runs in every mode, even "off". The heater control switch is brand new. Any thoughts?