Operation

OPERATION

The rear evaporator temperature sensor monitors the surface temperature of the rear A/C evaporator and supplies an input signal to the A/C-heater control. The A/C-heater control uses the rear evaporator temperature sensor input signal to optimize rear A/C system performance and to protect the rear A/C system from evaporator freezing. The rear 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 rear A/C evaporator decreases, the internal resistance of the rear evaporator temperature sensor decreases.

The A/C-heater control uses the monitored voltage reading as an indication of rear evaporator temperature. The 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 cycle the rear compressor clutch as necessary to optimize rear A/C system performance and to protect the system from evaporator freezing.

The rear evaporator temperature sensor is diagnosed using a scan tool.

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