1998 GMC Sonoma Owner's Manual - Page 80

NOTICE: Your engine is designed to work withthe electronics inyour vehicle. If you add electrical parts oraccessories, you could change the way the engine operates. Before adding electrical equipment, check withyour dealer. If you don't, your engine mightnot perform properly. If you ever haveto have your vehicle towed, see the part of this manual that tells how to do it without damaging your vehicle. See "Towing Your Vehicle" in the Index. To Use the Engine Coolant Heater 1. Turn off the engine. 2. Open the hood and unwrap the electrical cord. The cord is located on the driver's side of the engine compartment, behind the underhood fuse block. 3. Plug it into a normal, grounded 110-volt AC outlet. Engine Coolant Heater (If Equipped) In very cold weather, 0°F (- 18 C ) or colder, the engine coolant heater can help. You'll get easierstarting 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. O 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.