Ambient Temperature Sensor / Switch HVAC: Description and Operation

The ambient temperature sensor is a variable resistor mounted to a bracket that is secured with a screw to the left side of the radiator yoke, behind the radiator grille and in front of the engine compartment.

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

The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal sent by the Front Control Module (FCM). The resistance in the sensor changes as temperature changes, changing the temperature sensor signal circuit voltage to the FCM. Based upon the resistance in the sensor, the FCM senses a specific voltage on the temperature sensor signal circuit. The FCM then translates the voltage into a temperature reading that it sent over the Programmable Communications Interface (PCI) data bus circuit to other modules utilizing temperature information.