2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 242

To use an accessory power outlet, remove the protective cap. When not in use, always cover the accessory power outlet with the protective cap. Notice: Leaving electrical equipment plugged in for an extended period of time while the vehicle is off will drain the battery. Power is always supplied to the outlets. Always unplug electrical equipment when not in use and do not plug in equipment that exceeds the maximum 20 ampere rating. Certain power accessory plugs may not be compatible to the accessory power outlet and could result in blown vehicle or adapter fuses. If you experience a problem, see your dealer for additional information on the accessory power plugs. 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. Notice: Adding any electrical equipment to the vehicle can damage it or keep other components from working as they should. The repairs would not be covered by the vehicle warranty. Do not use equipment exceeding maximum amperage rating of 20 amperes. Check with your dealer before adding electrical equipment. When adding electrical equipment, be sure to follow the proper installation instructions included with the equipment. Notice: Improper use of the power outlet can cause damage not covered by the vehicle warranty. Do not hang any type of accessory or accessory bracket from the plug because the power outlets are designed for accessory power plugs only. 4-18