In-Vehicle Temperature Sensor

The in-vehicle temperature sensor is a temperature-sensitive resistor whose resistance varies inversely with temperature; as in-vehicle air temperature increases, resistance decreases and, as in-vehicle air temperature decreases, resistance increases. The HVAC programmer monitors the in-vehicle temperature signal and uses it to help determine command signals.

A hose duct connects the in-vehicle temperature sensor housing to an aspirator; air flow through the heater and A/C module creates a slight vacuum at the aspirator end of the hose. This vacuum draws in-vehicle air over the sensor, improving the accuracy of the in-vehicle temperature reading.