Wrangler 2WD V6-3.8L (2008)
Evaporator Temperature Sensor / Switch: Description and Operation
Operation
OPERATION
The evaporator temperature sensor monitors the surface temperature of A/C evaporator and supplies an input signal to the cabin compartment node
(CCN). The CCN 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 CCN 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 CCN uses the monitored voltage reading as an indication of evaporator temperature. The CCN 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 compressor clutch off and on
as necessary to optimize A/C system performance and to protect the A/C system from evaporator freezing See: Heating and Air
Conditioning/Compressor HVAC/Description and Operation/A/C Compressor - Operation.
The evaporator temperature sensor is diagnosed using a scan tool.
The evaporator temperature sensor cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
