1994 GMC Suburban Owner's Manual - Page 76

In very cold weather, 0°F (- 18OC) or colder, the engine coolant heater can help. You'll get easier starting better fuel economy during engine and warm-up. Usually, the coolant heater should be plugged in a minimum of four hours prior to starting your vehicle. To use the coolant heater: 1. Turn off the engine. 2. Open the hood and unwrap the electrical cord. 3. Plug it into a normal, grounded 110-volt outlet. NOTICE: After you've used the coolant heater, be sure to store the as cord it was before to keep away from moving engine parts. you it If don't, it could damaged. be How long should you keep the coolant heater plugged in? The answer depends on the weather, the kind of oil you have, and some other things. Instead of trying to list everything here, we ask that you contact a GM dealer in the area where you'll be parking your vehicle. The dealer can give you the best advice forthat particular area. 2-20