RAM 3500 Chassis Cab Truck 2WD L6-6.7L DSL Turbo (2010)
Evaporator Temperature Sensor / Switch: Description and Operation
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 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 Engine Control Module (ECM), depending on engine application, 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 See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures.
The evaporator temperature sensor cannot be adjusted or repaired and must be replaced if inoperative or damaged.
