Theory Of Operation

The HVAC A/C heater control uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C heater control to assure that they are in range. An active Diagnostic trouble Code (DTC) indicates that a sensor is out of range. A stored DTC indicates that the sensor was out of range but is currently within range.

A sun sensor is not a thermistor type sensor but is more accurately a photo diode. For this reason the sun sensor responds to sun light intensity rather than temperature. The sun sensor converts sunlight intensity to an electrical voltage which provides data to the A/C heater control to help determine proper mode and blend door positions and blower motor speeds. The sun sensor assembly is also used to sense day and night conditions for automatic headlight control if equipped.