1996 GMC Sonoma Owner's Manual - Page 61

Engine Coolant Heater (Option) 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 1 IO-volt AC outlet. 4.3L Engine 2.2L Engine In very cold weather. 0°F (- 18°C) or colder. the engine coolant heater can help. You'll get easier starting and better fuel economy during engine warm-up. Usually. the coolant heater should be plugged in a minimum of four hours prior to starting your vehicle. 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. Plug the cord into a properly grounded three-prong 110-volt AC outlet. If the cord won't reach,use a heavy-duty three-prong extension cord rated for at least 15 amps. 2-13