2011 Chevrolet Silverado 1500 Regular Cab Owner's Manual - Page 320

9-36 Driving and Operating Retained Accessory Power (RAP) The following vehicle accessories can be used for up to 10 minutes after the engine is turned off: ... Engine Coolant Heater The engine heater can provide easier starting and better fuel economy during engine warm-up in cold weather conditions at or below −18°C (0°F). Vehicles with an engine heater should be plugged in at least four hours before starting. An internal thermostat in the plug-end of the cord may exist which will prevent engine coolant heater operation at temperatures above −18°C (0°F). If the vehicle has a diesel engine, see the Duramax Diesel supplement for more information. To Use the Engine Coolant Heater 1. Turn off the engine. 2. Open the hood and unwrap the electrical cord. The cord is secured to the Engine Compartment Fuse Block with a clip. Carefully remove the wire tie which bundles the electrical plug. Do not cut the electrical cord. 3. Plug the cord into a normal, grounded 110-volt AC outlet. Audio System Power Windows OnStar System (if equipped) Sunroof (if equipped) These features work when the key is in ON/RUN or ACC/ ACCESSORY. Once the key is turned from ON/RUN to LOCK/OFF, the windows and sunroof continue to work up to 10 minutes until any door is opened. The radio continues to work for up to 10 minutes or until the driver door is opened. { WARNING Plugging the cord into an ungrounded outlet could cause an electrical shock. Also, the wrong kind of extension cord could overheat and cause a fire. You could be seriously injured. (Continued)