2012 GMC Sierra Owner's Manual - Page 148

5-10 Instruments and Controls Certain power accessory plugs may not be compatible to the accessory power outlet and could overload vehicle or adapter fuses. If a problem is experienced, see your dealer. When adding electrical equipment, be sure to follow the proper installation instructions included with the equipment. See Add-On Electrical Equipment on page 9‑105. Notice: Hanging heavy equipment from the power outlet can cause damage not covered by the vehicle warranty. The power outlets are designed for accessory power plugs only, such as cell phone charge cords. The accessory power outlets are powered, even when the ignition is in LOCK/OFF. Continuing to use power outlets while the ignition is in LOCK/OFF may cause the vehicle's battery to run down. Cigarette Lighter To use the cigarette lighter, push it in all the way, and let go. When it is ready for use, the lighter pops back out. Notice: Holding a cigarette lighter in while it is heating does not let the lighter back away from the heating element when it is hot. Damage from overheating can occur to the lighter or heating element, or a fuse could be blown. Do not hold a cigarette lighter in while it is heating. { WARNING Power is always supplied to the outlets. Do not leave electrical equipment plugged in when the vehicle is not in use because the vehicle could catch fire and cause injury or death. Notice: Leaving electrical equipment plugged in for an extended period of time while the vehicle is off will drain the battery. Always unplug electrical equipment when not in use and do not plug in equipment that exceeds the maximum 20 ampere rating.