1994 GMC Suburban Owner's Manual - Page 194

Run your engine only as long as you must. This saves fuel. When you run the engine, make it go a little faster than just idle. That is, push the accelerator slightly. This uses less fuel for heat that you get and it keeps the the battery (or batteries) charged. You will need a well-charged battery (or batteries) to restart the vehicle, and possibly for signalinglater on with your headlights. Let the heater run for awhile. If you have a diesel engine, you may have to run it at ahigher speed to get enough heat. Then, shut the engine off and close the window almost all the way to preserve the heat. Start the engine again and repeat this only when you feel really uncomfortable from the cold. But do it as little as possible. Preserve the fuel as long as you can. To help keep warm, you can get out of the vehicle and do some fairly vigorous exercises every half hour or so until help comes. Power Winches If you wish to use a power winch on your vehicle, only use it when your vehicle is stationary or anchored. NOTICE: When operating a power winch on your vehicle, always leave the transmission in "N" (Neutral). Leaving a automatic transmission in "P"(Park) while using a power winch may damage the transmission. Also, leaving automatic or manual a transmission in gear while using an power winch may damage the transmission. Use the regular brakes, set the parking brake, or block the wheels to keep your vehicle from rolling. 4-34