The engine heater can provide easier starting and better fuel economy during engine warm-up in cold weather conditions at or below 0°F (- 18°C). 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 0°F (-18°C).

If the vehicle has the DURAMAX® Diesel engine, see the DURAMAX® Diesel manual for more information.

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, near the power steering fluid reservoir.
3. Plug the cord into a normal, grounded 110-volt AC outlet.

Caution: 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 will not reach, use a heavy-duty three-prong extension cord rated for at least 15 amps.

4. Before starting the engine, be sure to unplug and store the cord as it was before to keep it away from moving engine parts. If you do not, it could be damaged.

The length of time the heater should remain plugged in depends on several factors. Ask a dealer/retailer in the area where you will be parking the vehicle for the best advice on this.

In very cold weather, 0°F (-18°C) or colder, the engine coolant heater can help by providing 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.

1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The cord is located in the engine compartment, on the passenger's side of the vehicle, near the right side auxiliary battery.
3. Plug it into a normal, grounded 110-volt AC outlet.

Caution: 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 will not reach, use a heavy-duty three-prong extension cord rated for at least 15 amps.

4. Before starting the engine, be sure to unplug and store the cord as it was before to keep it away from moving engine parts. If you don't, it could be damaged.

How long should you keep the coolant heater plugged in? The answer depends on the outside temperature. You may wish to use your coolant heater to improve ease of starting at temperatures between 0°F (-18°C) and -20°F (-29°C). Keep the coolant heater plugged in for a minimum of four hours. At temperatures below -20°F (-29°C), the coolant heater should remain plugged in for at least eight hours. It will not harm either the coolant heater or the vehicle to leave the coolant heater plugged in longer than the times stated. Be sure to remove and store the cord before starting the engine. See Diesel Fuel Requirements and Fuel System for information on what fuel to use in cold weather.