2008 GMC Sierra 1500 Pickup Owner's Manual - Page 256

PROG (Program): Press this button to go to the next preset radio station or channel set on the main radio. This function is inactive, with some radios, if the front seat passengers are listening to the radio. When a CD or DVD audio disc is playing, press this button to go to the beginning of the CD or DVD audio. This function is inactive, with some radios, if the front seat passengers are listening to the disc. When a disc is playing in the CD or DVD changer, press this button to select the next disc, if multiple discs are loaded. This function is inactive, with some radios, if the front seat passengers are listening to the disc. When a DVD video menu is being displayed, press the PROG button to perform the menu function, enter. Audio Steering Wheel Controls Vehicles with audio steering wheel controls could differ depending on your vehicle's options. Some audio controls can be adjusted at the steering wheel. They include the following: Theft-Deterrent Feature THEFTLOCK® is designed to discourage theft of your vehicle's radio. The feature works automatically by learning a portion of the Vehicle Identification Number (VIN). If the radio is moved to a different vehicle, it does not operate and LOC, LOCK, or LOCKED could display. With THEFTLOCK activated, the radio does not operate if stolen. ® xw(Next/Previous): Press the down or up arrow to go to the next or to the previous radio station stored as a favorite. When a CD/DVD is playing, press the down or up arrow to go to the next or to the previous track or chapter. g (Mute/Voice Recognition): Press and release this button to silence the vehicle speakers only. The audio of the wireless and wired headphones, if your vehicle has these features, does not mute. Press and release this button again, to turn the sound on. 3-120