I know that the compressor cycles on and off with the AC on controls set to deffrost/ bi mode/ etc...) but if I have the thermostat on the heat should my compressor still cycle on and off?
It's the outside air temp that makes the difference. When the outside air temp is 32 or below, the humidity drops pretty low as the moisture in the air freezes. So the ac compressor doesn't have to run when the outside air temp is 32 or below.
I believe (and could be wrong - working with a poor memory) that the temperature sensor is located along the lower bumper cover (or whatever it's called) off center about 18". It's small.