Sunload Sensor
WARNING: This page is about a different car, the 2016 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.
The sunload sensor supplies information to the dual-zone HVAC control module indicating sunload. When sunload is detected, the information from the sensor is used to lower the A/C temperature output to compensate for radiant heat warming the vehicle interior and occupants.