Ambient Temperature Sensor / Switch HVAC: Description and Operation
SENSOR-AMBIENT AIR TEMPERATUREDESCRIPTION
The ambient air temperature sensor is a variable resistor that monitors the air temperature outside of the vehicle. The ambient air temperature sensor is mounted onto the inside of the front bumper beam and its data is used by the heating-A/C system to maintain optimum cabin temperature levels.
OPERATION
The ambient air temperature sensor is a variable resistor that operates on a ground circuit and a 5-volt reference signal circuit sent by the front control module (FCM) 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 A/C-heater control and other various vehicle control modules.
The ambient air temperature sensor is diagnosed using the scan tool.
The ambient air temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.