Ambient Temperature Sensor / Switch HVAC: Description and Operation
SENSOR-AMBIENT TEMPERATUREDESCRIPTION
Ambient air temperature is monitored by the compass/temperature display unit. The Totally Integrated Power Module (TIPM) receives a hard wired input from the ambient temperature sensor. The info is then transferred over the Controller Area Network (CAN) data bus to be displayed and filtered by the instrument cluster or Cab Compartment Node (CCN). The ambient temperature sensor is a variable resistor mounted to a bracket that is secured with a nut to the bracket in front of the A/C condenser, behind the radiator grille.
The ambient temperature sensor cannot be adjusted or repaired and, if inoperative or damaged, must be replaced.
OPERATION
The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal. The resistance in the sensor changes as temperature changes, changing the temperature sensor signal circuit voltage to the Totally Integrated Power Module (TIPM). Based upon the resistance in the sensor, the instrument cluster or Cab Compartment Node (CCN) display senses a specific voltage on the Controller Area Network (CAN) data bus circuit, which corresponds to a specific temperature. The compass/temperature display unit then displays the proper ambient temperature.