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 powertrain control module (PCM) or the engine control module (ECM) (depending on engine application) 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.

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