2002 GMC Envoy Owner's Manual - Page 178

Automatic Dual Zone Comfort Control System (Option) The display will show the temperature increasing as you turn the knob clockwise. When this knob is adjusted, the word DRIVER will be displayed under the temperature setting. If the passenger's set temperature has not been adjusted, this knob controls both the driver's and passenger's air temperature. Passenger's Side Temperature Knob The passenger's side knob can be used to change the temperature of the air coming through the system on the passenger's side of the vehicle. Turn the knob counterclockwise to lower the cabin temperature. The display will show the temperature decreasing as you turn the knob counterclockwise. Turn the knob clockwise to increase the cabin temperature. The display will show the temperature increasing as you turn the knob clockwise. When this knob is adjusted, only the word PASS will be displayed under the temperature setting. The temperature to the rear seat area is controlled by using this knob. Once this knob is used, the passenger's set temperature will remain independent of the driver's until the ignition has been turned off. With this system, you can select different comfort control settings for the driver and passengers. Driver's Side Temperature Knob The driver's side knob is used to adjust the temperature of the air coming through the system on the driver's side. Turn the knob counterclockwise to lower the cabin temperature. The display will show the temperature decreasing as you turn the knob counterclockwise. Turn the knob clockwise to increase the cabin temperature. 3-4