Evaporator Discharge Air Temperature Sensor

WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

The evaporator discharge air temperature sensor contains a thermistor. The resistance of this thermistor varies by a specific amount based on the evaporator discharge air temperature. The HVAC module measures a voltage ratio between the reference voltage it supplies to the sensor and the sensor return voltage to determine this resistance and the associated discharge air temperature.

The evaporator discharge air temperature sensor maintains evaporator core temperature and prevents icing of the evaporator core. It does this by signaling the HVAC module to switch off the A/C request signal to the instrument cluster when the evaporator discharge air temperature sensor reading falls below acceptable levels. The A/C request will be switched back on when the evaporator temperature rises above acceptable levels.

The evaporator discharge air temperature sensor can be accessed from below the LH side of the instrument panel to the right of the accelerator pedal.