2002 GMC Envoy Owner's Manual - Page 180

To find your comfort setting, start with a 74_ F (23_C) temperature setting and allow about 20 minutes for the system to regulate. Turn the driver's or passenger's side temperature knob clockwise or counterclockwise to adjust the temperature setting as necessary. If you choose the temperature setting of 60_F (15_C), the system will remain at the maximum cooling setting and fan speed. If you choose the temperature setting of 90_F (32_C), the system will remain at the maximum heat setting and fan speed. Choosing either maximum setting will not cause the system to heat or cool any faster. Be careful not to cover the sensor located on the top of the instrument panel near the windshield. This sensor regulates air temperature based on sun load, and also turns on your headlamps. The EXT (exterior) temperature sensor is located in the front of the vehicle behind the grille. The displayed temperature is most accurate after the vehicle has been moving for a few minutes. If the vehicle is stopped and then restarted within 2 1/2 hours, the sensor will be hot from the engine heat. In this case, the temperature first displayed will continue to be the temperature that was displayed before the vehicle was turned off. The display will update after the vehicle has been moving for a few minutes and the sensor has a chance to cool down to the actual temperature. To avoid blowing cold air in cold weather, the system will delay turning on the fan until warm air is available. The length of delay depends on the engine coolant temperature. Pushing the fan switch will override this delay and change the fan to a selected speed. Manual Operation You may manually adjust the air delivery mode or fan speed. Use the mode button to cycle through the following four air delivery modes: (Panel): This setting will deliver air to the instrument panel outlets. (Bi-Level): This setting will deliver warmer air to the floor and cooler air to the instrument panel outlets. (Floor): This setting will deliver air to the floor outlets. (Defog): This setting will deliver air to the floor and windshield outlets. OFF: Press this button to turn the system off. Some fresh air will continue to flow through the vehicle from the floor outlets. The system will try to maintain the previously chosen temperature setting. 3-6