2002 Buick Rendezvous Owner's Manual - Page 227

Heating Turn the temperature knob to the desired interior temperature to warm the air. In the lower mode, outside air will be brought in and sent through the floor outlets. The heater works best if you keep your windows closed while using it. The bi-level setting is designed for use on sunny days when the air is only moderately warm or cool. On days like these, the sun may adequately warm your upper body, but your lower body may not be warm enough. For the best results, move the temperature knob to the middle position, and then adjust it for comfort. Your vehicle has a computer controlled transaxle designed to warm up the engine faster when the outside temperature is 35_F (2_C) or colder. You may notice that the transaxle will shift at a higher vehicle speed until the engine is warmed up. This is a normal condition designed to provide heat to the passenger compartment and defrost the windows more quickly. If your vehicle is equipped with an engine coolant heater and you use it during cold weather, 0_F (-18_C) or lower, your heating system will provide heat more quickly because the engine coolant is already warmed. See "Engine Coolant Heater" in the Index. Defogging and Defrosting Your system has two settings for clearing the front and side windows. To defrost the windows quickly, press the defrost button and set the temperature to 90_F (32_C) and select a high fan speed. To warm passengers while keeping the window clear, select the defog mode with the mode button (the defog symbol will be lit). Select the fan speed for comfort and windshield clearing performance. 3-8