RAM 1500 Truck 2WD V8-5.7L VIN 2 (2006)
Evaporator Temperature Sensor / Switch: Description and Operation
The evaporator temperature sensor is a two-wire temperature sensing element located at the coldest point on the face of the A/C evaporator. The probe
(1) for evaporator temperature sensor is attached to the evaporator coil fins. The wire lead (2) for evaporator temperature sensor is routed through an
opening at the back of the HVAC housing and the connector (3) is attached to the HVAC wire harness.
The evaporator temperature sensor monitors the surface temperature of 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. 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 cycle the
A/C compressor 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.
The evaporator temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.
