Cabin Temperature Sensor / Switch: Description and Operation

Sensor Assembly:

DESCRIPTION
Passenger compartment air temperature is sampled by the Temperature Sensor Assembly to allow the Automatic Temperature Control system to maintain a constant temperature inside the vehicle.

OPERATION
The sensor assembly contains a bimetallic sensor that senses the passenger compartment air temperatures. The bimetallic sensor controls a vacuum modulator and higher temperatures cause higher vacuum gauge readings. A bias to the vacuum output level is accomplished by means of a control arm attached by a cable assembly to the temperature control lever. Thus, the modulated vacuum output is the result of the effects of the control bias and the temperature of the air across the bimetallic sensor. The sensor assembly also includes an aspirator or venturi (as it is called in previous ATC systems) and a moulded sensor inlet seal. The aspirator provides a very small vacuum to draw a continuous sampling of passenger compartment air across the air temperature sensing bimetal. Primary air is ducted to the sensor through a tube from the blower stream providing the power to operate the aspirator for the in-vehicle sensor.