Evaporator Temperature Sensor - Operation

OPERATION

The evaporator temperature sensor monitors the surface temperature of A/C evaporator and supplies an input signal to the Cabin Compartment Node (CCN). The CCN 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 CCN through sensor ground circuit and a 5-volt reference signal circuit. As the temperature of the A/C evaporator decreases, the internal resistance of the evaporator temperature sensor decreases.

The CCN uses the monitored voltage reading as an indication of evaporator temperature. The CCN is programmed to respond to this input by requesting the Powertrain Control Module (PCM) or the Engine Control Module (ECM) (depending on engine application) to cycle the A/C clutch off and on as necessary to optimize A/C system performance and to protect the A/C system from evaporator freezing A/C Compressor - Operation.

The evaporator temperature sensor is diagnosed using a scan tool Testing and Inspection.

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