Parental Control
The RSE system may have a Parental Control feature, depending on the radio. To enable Parental Control, press and hold the radio power button for more than two seconds to stop all system features such as: radio, video screen, RSA, DVD and/or CD.
While Parental Control is on, 
displays.
When the radio is turned back on, Parental Control is unlocked.
See also:
Exterior Lamp Controls
The exterior lamp control is on the turn signal/lane change lever.
(Exterior Lamp Control): Operates
the exterior lamps. Turn to one of the following positions:
(Off): Briefly turn to this pos ...
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.
...
Compass Calibration
The compass can be manually calibrated. Only calibrate the compass in a magnetically clean and safe location, such as an open parking lot, where driving the vehicle in circles is not a danger.
It is ...