Cabin Temperature Sensor / Switch: Description and Operation

In-Car Temp Sensor:

DESCRIPTION
The Automatic Temperature Control (ATC) system uses various sensors which return electrical signals to the Body Control Module (BCM). The In-Car Temperature Sensor is used on ATC equipped vehicles only. The In-Car Temperature Sensor is part of motorized aspirator assembly that is mounted in the instrument panel. A small fan (in the sensor) draws air through an intake in the instrument panel (behind the name plate). This air flows over a thermistor which measures interior vehicle temperatures. The ATC system then makes adjustments to maintain optimum passenger compartment comfort.

OPERATION
The In-Car Sensor will automatically turn on when a vehicle door is opened. If the door is left open, the In-Car Sensor will automatically turn off within approximately 5 minutes. If the door is then closed, but there is no ignition start, the In-Car Sensor will automatically turn off after approximately 2 minutes. After the vehicle has been driven, the In-Car Sensor will turn off immediately when the ignition is turned off. The aspirator motor in the In-Car Sensor operates whenever the ignition switch is on (even when the ATC system off button is pushed). If the In-Car Sensor is open or shorted on this system, the digital display will turn off. Then the system defaults to manual operation.

NOTE: The In-Car Temperature Sensor assembly is not serviceable and must be replaced if found to be defective.