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:
Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position.
• The ignition should turn to LOCK/OFF only when the shift lever is in P (Park).
†...
All Terrain chassis and suspension
Based on the chassis of the 2011 Sierra HD trucks, the All Terrain HD
features a fully boxed steel frame with exceptional strength and torsional
stiffness. It incorporates the production models' n ...
Manual Operation
The air delivery mode or fan speed can be manually adjusted.
(Fan Control): Press to increase or decrease the fan speed.
Pressing or
while in automatic control places the fan speed under manual ...