2008 GMC Sierra 1500 Pickup Owner's Manual - Page 257

If your vehicle has the navigation system, press and hold this button for longer than one second to initiate voice recognition. See "Voice Recognition" in the Navigation System manual for more information. If your vehicle has OnStar®, press and hold this button for longer than one second to interact with the OnStar® system. If your vehicle also has the navigation system, press and hold this button for longer than one second to initiate voice recognition and say "OnStar" to enter OnStar® mode. See the OnStar® System on page 2-45 in this manual for more information. SRCE (Source): Press this button to switch between the radio (AM, FM), XM™ (if equipped), CD, and if your vehicle has these features, DVD, front auxiliary, and rear auxiliary. + e − e (Volume): Press the plus or minus volume button to increase or to decrease the radio volume. Radio Reception Frequency interference and static can occur during normal radio reception if items such as cell phone chargers, vehicle convenience accessories, and external electronic devices are plugged into the accessory power outlet. If there is interference or static, unplug the item from the accessory power outlet. AM The range for most AM stations is greater than for FM, especially at night. The longer range can cause station frequencies to interfere with each other. For better radio reception, most AM radio stations boost the power levels during the day, and then reduce these levels during the night. Static can also occur when things like storms and power lines interfere with radio reception. When this happens, try reducing the treble on your radio. ¨(Seek): Press the seek arrow to go to the next radio station while in AM, FM, or XM™ (if equipped). Press the seek arrow to go to the next track or chapter while sourced to the CD or DVD slot. Press the seek arrow to go to the next disc while sourced to a six-disc CD player, if multiple discs are loaded. FM Stereo FM stereo gives the best sound, but FM signals only reach about 10 to 40 miles (16 to 65 km). Tall buildings or hills can interfere with FM signals, causing the sound to fade in and out. 3-121