Chevrolet Silverado Classic 2007 Owner's Manual page 238

Sensors
The solar sensor, located in the defrost grille,
that is in the middle of the instrument panel,
monitors the solar radiation. Do not cover the
solar sensor or the system will not work properly.
238
There is an interior temperature sensor located
next to the steering wheel that measures the
temperature of the air inside your vehicle.
There is also an exterior temperature sensor
located behind the front grille. This sensor reads
the outside air temperature and helps maintain
the temperature inside the vehicle. Any cover
on the front of the vehicle could cause a
false reading in the displayed temperature.