Cadillac 2008 SRX Owner's Manual page 167

Sensors
There is a solar sensor located on top of the instrument
panel, near the windshield.
An ambient sensor is located behind the grille in front of
the vehicle.
These sensors help the climate control system
automatically control the temperature setting. The
system can supply cooler air to the side of the vehicle
facing the sun. The recirculation mode will also be used
as needed to maintain cool outlet temperatures.
Do not cover any of the sensors or the climate control
system might not work properly.
There is an interior
temperature sensor
located below the climate
control system next to
the steering wheel.
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