Turning the Rear Vision Camera System Off or On
To turn off the rear vision camera system, press and hold 
, located on the inside rearview mirror, until the left indicator light turns off.
The rear vision camera display is now disabled.
To turn the rear vision camera system on again, press and hold until the left indicator
light illuminates. The rear vision camera system display is now enabled and the display will appear in the mirror normally.
See also:
Lockout Protection
This feature protects you from locking the key in the vehicle when the key is in the ignition and a front door is open.
If the driver side power door lock switch is pressed when the driver door is op ...
Online Owner Center
Manage your vehicle (U.S.) at gmc.com. Click on “Owners,” then “Manage My GMC/Owners Login.”
Information and services customized for your specific vehicle — all in one convenient place.
...
Overview
The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck
capability combined with greater off-road versatility. It is highlighted by a
bold exterior design, enhanced all-terrain ...