/// Generally the tube that runs to the evaporating coil under the dash holds a fluid and connects to a bellows resting against the micro switch. The fluid expands and contracts moving the bellows slightly and that opens and closes the switch. The knob, again, generally, positions the switch closer or further away from the bellows. The knob isn't actually connected to a wire. The switch is connected to the wire. You could put your switch in series so that the air would not be on unless the switch is closed or in parallel so that it would be on all the time if the switch is closed.