Ambient Air Temperature (AAT) Sensor (if equipped)
WARNING: This page is about a different car, the 2016 Ford Transit-350 HD, 2016 Ford Transit-350, 2016 Ford Transit-250, and 2016 Ford Transit-150. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
To see if a vehicle should have an Ambient Air Temperature (AAT) sensor (also called OAT sensor), go to the Ford PTS website, enter the VIN and in the OASIS tab, select HVBoM (Historical Vehicle Bill of Material), select Electrical, then Modules Switches and Relays. If equipped, the sensor will be listed as SENDER ASY - TEMPERATURE, with Engineering (base) Part Number 10K936.
The Ambient Air Temperature (AAT) sensor contains a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The Ambient Air Temperature (AAT) sensor is hardwired to the PCM through separate input and return circuits. If the outside air temperature is below approximately 0 °C (32 °F), the PCM does not allow the A/C compressor clutch to engage.