Grand Cherokee 2WD V8-4.7L VIN N (2000)
Driver/Vehicle Information Display: Description and Operation
Ambient Temperature Sensor
AMBIENT TEMPERATURE SENSOR
DESCRIPTION
Ambient air temperature is monitored by the Electronic Vehicle Information Center (EVIC) through ambient temperature messages received from
the Body Control Module (BCM) over the Programmable Communications Interface (PCI) data bus network. The BCM receives a hard wired
input from the ambient temperature sensor. The ambient temperature sensor is a variable resistor mounted to a bracket that is secured with a screw
to the right side of the headlamp mounting module grille opening, behind the radiator grille and in front of the engine compartment.
Refer to Body Control Module in the Description and Operation section of Powertrain Management/Computers and Control Systems/Body
Control Module for more information on the BCM. The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it
must be replaced.
OPERATION
The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal sent to it by the BCM. The resistance in the
sensor changes as temperature changes, changing the temperature sensor signal circuit voltage to the BCM. Based upon the resistance in the
sensor, the BCM senses a specific voltage on the temperature sensor signal circuit, which it is programmed to correspond to a specific temperature.
The BCM then sends the proper ambient temperature messages to the EVIC over the PCI data bus.
