Horn
Pressa 
on the steering wheel pad
to sound the horn.
See also:
Infotainment System Overview
The infotainment system is controlled by using the buttons on the faceplate and
the touch screen. See “Infotainment Control Buttons” in this section for more information.
...
Vehicles with Navigation System
The RVC system is designed to help the driver when backing up by displaying a view of the area behind the vehicle. When the vehicle is shifted into R (Reverse), the video image appears on the navigati ...
2011 GMC Sierra 2500HD Review
The "professional grade" brand unveiled the 2011 GMC Sierra Heavy Duty lineup
at the 2010 NTEA Work Truck Show. Most of the technical specifications of GM's
HD pickups are identical, but ...