GMC 2009 Yukon XL Owner's Manual page 168

Rear Vision Camera Location
The image is provided by the camera located above the
license plate.
The camera uses a special lens. The distance of the
image that appears on the screen differs from the actual
distance. The area displayed by the camera is limited.
The camera does not display objects which are close to
either corner of the bumper or under the bumper. The
area displayed on the screen can vary according to
vehicle orientation or road conditions.
The following illustration shows the field of view that the
camera provides.
2-62