Grand Cherokee 4WD V8-5.2L VIN Y (1998)
Ambient Temperature Sensor / Switch HVAC: Description and Operation
Models with the optional Automatic Temperature Control (ATC) system use an input from the ambient temperature sensor. The sensor is located
in front of the condenser and behind the radiator grille on the center radiator support.
The ambient temperature sensor is hard-wired to the Body Control Module (BCM). The BCM places an ambient temperature message on the
CCD data bus for use by the overhead console for the thermometer function, and for use by the ATC control module.
The ambient temperature sensor is a Negative Temperature Coefficient (NTC) thermistor or temperature sensitive resistor. The ATC control
module uses this sensor input to monitor the outside air temperature. However, because heat from the radiator and condenser can affect the
accuracy of the input from this sensor when the vehicle is not moving, this input is only used by the ATC system when the vehicle is in motion.
The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.