Ambient Temperature Sensor
WARNING: This page is about a different car, the 2004 Dodge Grand Caravan, 2004 Dodge Caravan, and 2004 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.
The ambient air temperature is monitored by the FCM and displayed by the CT/CMTC/EVIC. The FCM receives a hard wire input from the ambient temperature sensor (ATS).
The ATS is a variable resistor that operates on a 5-volt reference signal circuit hard wired from the FCM. The resistance in the ATS changes as the outside temperature rises or falls. The FCM senses the change in reference voltage through the ATS resistor. Based on the resistance of the ATS, the FCM is programmed to correspond to a specific temperature. The FCM stores and filters the ambient temperature data and transmits this data to the CMTC/EVIC via the PCI Bus. The ATS cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.