Sunload Sensor (Solar Radiation Sensor)
WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The solar radiation sensor supplies information to the HVAC module indicating sunload strength, and (to an extent) direction. The solar radiation sensor is located on the center of the instrument panel at the base of the windshield.