Ambient Temperature Sensor
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Sensor is located on center of lower radiator support. The Ambient Air Temperature Sensor provides the IPM with temperature of the air outside the vehicle. The temperature is displayed on the HVAC Control Head. As the air temperature increases, resistance decreases and the remaining voltage is sent back to the IPM providing input from the sensor.