Evaporator Temperature Sensor - Operation

OPERATION

The evaporator temperature sensor monitors the temperature of the conditioned air downstream of the A/C evaporator and supplies an input signal to the A/C heater module. The A/C heater 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 A/C heater module through 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 A/C heater module uses the monitored voltage reading as an indication of evaporator temperature. The A/C heater module is programmed to respond to this input by requesting the Powertrain Control Module (PCM) to cycle 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 Testing and Inspection.

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