2007 Cadillac STS Owner's Manual - Page 115

Engine Coolant Heater Your vehicle may be equipped with an engine coolant heater. In very cold weather, 0°F (−18°C) or colder, the engine coolant heater can help. You will 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. At temperatures above 32°F (0°C), use of the coolant heater is not required. Your vehicle may also have an internal thermostat in the plug end of the cord. This will prevent operation of the engine coolant heater when the temperature is at or above 0°F (−18°C) as noted on the cord. To Use the Engine Coolant Heater 1. Turn off the engine. 2. Open the hood and unwrap the electrical cord. For the 3.6L V6 engine, the cord is located in the engine compartment on the passenger's side of the vehicle in front of the fuse block. For the 4.6L V8 engine, the cord is located in the engine compartment on the driver's side of the vehicle near the inner fender and above the strut. For the 4.4L V8 engine, the cord is located in the front of the engine compartment, on the passenger's side of the vehicle. The plug will be inside the upper grille cutout. 3. You must remove the plastic cap to access the plug. 115