Sensor, Evaporator Temperature: Operation

The evaporator temperature sensor monitors the surface temperature of A/C evaporator and supplies an input signal to the Heating, Ventilation, and Air Conditioning (HVAC) module. The HVAC module uses the evaporator temperature sensor input signal to optimize A/C system performance and to protect the A/C system from evaporator freezing. The evaporator temperature sensor will change its internal resistance in response to the temperatures it monitors and is connected to the HVAC module through a sensor ground circuit and a 5 volt Direct Current (DC) reference signal circuit. As the temperature of the A/C evaporator decreases, the internal resistance of the evaporator temperature sensor decreases.

The HVAC module uses the monitored voltage reading as an indication of evaporator temperature. The HVAC module is programmed to respond to this input by cycling the A/C clutch as necessary to optimize A/C system performance and to protect the A/C system from evaporator freezing.

The evaporator temperature sensor is diagnosed using a scan tool. Refer to HEATING & AIR CONDITIONING (ATC) DIAGNOSTIC CODE INDEX .

The evaporator temperature sensor cannot be adjusted or repaired and must be replaced if inoperative or damaged.

Evaporator Temperature Sensor - Ohms Testing Chart