Front Evaporator Temperature Sensor - Operation

OPERATION

The front evaporator temperature sensor monitors the surface temperature of the front A/C evaporator and supplies an input signal to the A/C-heater control. The A/C-heater control uses the front evaporator temperature sensor input signal to optimize front A/C system performance and to protect the front A/C system from evaporator freezing. The front evaporator temperature sensor will change its internal resistance in response to the temperatures it monitors and is connected to the A/C-heater control through sensor ground circuit and a 5-volt reference signal circuit. As the temperature of the front A/C evaporator decreases, the internal resistance of the front evaporator temperature sensor decreases.

The A/C-heater control uses the monitored voltage reading as an indication of front evaporator temperature. The A/C-heater control is programmed to respond to this input by requesting the Engine Control Module (ECM) to adjust the front compressor swash plate angle as necessary to optimize A/C system performance and to protect the A/C system from evaporator freezing.

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

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