GMC 2012 Sierra Denali Owner's Manual page 297

The camera is located in the bezel
for the tailgate handle.
This shows the field of view that the
camera provides.
A. View displayed by the camera
A. View displayed by the camera
B. Corners of the rear bumper
Displayed images may be further or
closer than they appear. The area
displayed is limited and objects
which are close to either corner of
the bumper or under the bumper do
not display.