Ambient Temperature Sensor / Switch HVAC: Description and Operation

Ambient air temperature is connected to the instrument cluster through a two-wire harness lead and connector of the vehicle electrical system. The instrument cluster sends out a message on the CAN bus to the ATC control module. The ambient temperature sensor is a variable resistor mounted to the front licence plate bracket.

The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal sent to it by the instrument cluster. The resistance in the sensor changes as temperature changes. Based upon the resistance in the sensor, the instrument cluster sends the ATC control module a specific voltage on the temperature sensor signal circuit, which is programmed to correspond to a specific temperature.

The ambient temperature sensor is diagnosed using the DRBIII(R) scan tool. Refer to Body Diagnostic Procedures.