Ambient Temperature Sensor

Ambient Temperature Sensor:

Ambient air temperature is monitored through ambient temperature messages received from the Front Control Module (FCM) over the Programmable Communications Interface (PCI) data bus circuit. The FCM 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 left side of the cooling module, behind the front grille.

For more information on the Front Control Module refer to the Electronic Control Modules section. The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The ambient temperature sensor is a variable resistor. A five-volt reference signal is sent to the sensor by the Front Control Module. The front control module monitors the return signal voltage on a dedicated temperature sensor signal circuit. Based upon the resistance in the sensor, the Front Control Module is programmed to correspond to a specific temperature. The Front Control Module then sends the proper ambient temperature messages over the PCI data bus circuit.

The HVAC temperature display function is supported by the ambient temperature sensor, a wiring circuit, the Front Control Module and the Programmable Communications Interface (PCI) data bus. If any portion of the ambient temperature sensor circuit fails, the Front Control Module should self-diagnose the circuit.