Dakota 4WD V8-4.7L Flex Fuel (2008)
Evaporator Temperature Sensor / Switch: Description and Operation
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 control. The A/C-heater control 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 control 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 A/C-heater control uses the monitored voltage reading as an indication of evaporator temperature and that conditions are correct to broadcast an A/C
request message on the controller area network (CAN) B bus, where it is read by the front control module (FCM). The FCM then requests the powertrain
control module (PCM) to cycle the A/C compressor clutch as necessary over the CAN C bus.
The evaporator temperature sensor is diagnosed using a scan tool.
The evaporator temperature sensor cannot be adjusted or repaired and must be replaced if inoperative or damaged.
