190E 2.6 (201.029) L6-2.6L (103.942) (1987)
Cabin Temperature Sensor / Switch: Description and Operation
In-Car Temperature Sensor
Interior Temperature Sensor
PURPOSE
The in-car (interior) temperature sensor, which is located in the headliner or in the dome/reading lamp, sends interior temperature information to the
push-button control unit for calculation of blend air flap position and other outputs.
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 TCC 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 TCC system.