Cabin Temperature Sensor / Switch: Description and Operation

In-Car Temperature Sensor Location:

In-Car Temperature Sensor

PURPOSE

The in-car (interior) temperature sensor, which is located in the overhead lamp, sends interior temperature information to the push-button control unit.

CONSTRUCTION

The in-car temperature sensor is a negative temperature coefficient (NTC) type resistor. As the surrounding temperature increases the resistance decreases.

OPERATION

When the ignition is switched "ON", a blower aspirator pulls interior air across the surface of the sensor element. The passing air produces a resistance value in the sensor. The resulting current flow in the sensor circuit is recognized by the ACC control unit as a measurement of the interior air temperature.
The constant air flow past the sensor, produced by the blower aspirator, increases the accuracy of the ACC system.