Cabin Temperature Sensor / Switch: Description and Operation

Fig. 3 System components:

The in-car-sensor assembly is connected to the aspirator suction nipple and the instrument panel. Air from the passenger compartment is drawn through the instrument panel opening past a temperature sensing thermistor located in the sensor assembly. Electrical resistance of the thermistor increases when in-vehicle air temperature decreases and decreases when the temperature increases. This action permits the system to detect in-vehicle air temperature changes.