Function
Turning the temperature dials adjusts a potentiometer. The potentiometer assumes a resistance value corresponding to the selected temperature and the pushbutton control module uses this value for comparison with the value measured by the heater core temperature sensor. On vehicles with automatic heater the outdoor temperature is measured in addition by comparing the value measured by the outdoor air temperature sensor.
The temperature dials allow the temperature for each side of the car to be set separately and infinitely between the two values
"Blue" = heater off and
"Red" = heater completely on