SENSOR-AMBIENT AIR TEMPERATURE
DESCRIPTION
The ambient air temperature sensor is a variable resistor that monitors the air temperature outside of the vehicle. The ATC system uses the sensor data to maintain optimum cabin temperature levels. The ambient air temperature sensor is mounted onto the top of the front bumper beam.
OPERATION
The ambient air temperature sensor is a variable resistor that operates on a 5-volt reference signal sent by the front control module (FCM). The ambient air temperature sensor is connected to the FMC through a two-wire lead and connector of the vehicle wire harness. The ambient air temperature sensor changes its internal resistance in response to changes in the outside air temperature, which either increases or decreases the reference signal voltage read by the FCM. The FCM converts and broadcasts the sensor data over the controller area network (CAN) B bus, where it is read by the ATC A/C-heater control and other vehicle control modules.
The ambient air temperature sensor is diagnosed using a scan tool (refer to 24 - HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING - HEATING AND A/C SYSTEMS and to 24 - HVAC Electrical Diagnostics for more information).
The ambient air temperature sensor cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
REMOVAL
1. Disconnect and isolate the negative battery cable.
2. Remove the grille (refer to 23 - BODY/EXTERIOR/GRILLE - REMOVAL).
3. Disconnect the wire harness connector (1) from the ambient air temperature sensor (2) located at the top of the front bumper beam (3).
4. Disengage the ambient air temperature sensor from the retaining tabs (4) and remove the sensor.
INSTALLATION
1. Install the ambient air temperature sensor (2) onto the top of the front bumper beam (3). Make sure that the retaining tabs (4) are fully engaged.
2. Connect the wire harness connector (1) to the ambient air temperature sensor.
3. Install the grille (refer to 23 - BODY/EXTERIOR/GRILLE - INSTALLATION).
4. Reconnect the negative battery cable.