F 150 4WD V8-4.6L VIN 8 (2010)
Evaporator Temperature Sensor / Switch: Description and Operation
Evaporator Temperature Sensor
The evaporator temperature sensor contains a thermistor. The resistance of this thermistor varies by a specific amount based on the evaporator
temperature. The HVAC module measures a voltage ratio between the reference voltage it supplies to the sensor and the sensor voltage to determine this
resistance and the associated evaporator temperature.
The evaporator temperature sensor maintains evaporator core temperature and prevents icing of the evaporator core. The temperature information from
the sensor is used by the HVAC module to switch off the A/C request signal to the IC when the evaporator temperature falls below acceptable levels
(slightly above the freezing point of water). The A/C request will be switched back on when the evaporator temperature rises above acceptable levels.
The evaporator temperature sensor electrical connector is located outside of the heater core and evaporator core housing behind the glove compartment,
with the sensor pigtail leading into the housing to the sensor probe which is inserted between the evaporator core fins.
The evaporator temperature sensor is not available as a separate component. To install a new evaporator temperature sensor, a new heater core and
evaporator core housing must be installed.
