2005 GMC Envoy Owner's Manual - Page 166

Turn the knobs on the control panel to choose a fan speed, temperature and direction of airflow. H (Panel): Selecting panel mode will deliver air to the four headliner outlets. Selecting bi-level mode will deliver warmer air to the third seat floor outlet and cooler air to the headliner outlets. Selecting floor mode will deliver air to the floor outlet located in the third seat area. Press the buttons at the bottom of the audio control panel to adjust the fan speed, mode and temperature for the rear passengers. The selections will be shown on the display. ) (Bi-level): 6 (Floor): 3-30 z9 y (Fan): Press the rear fan control button with the arrow pointing right to turn the rear climate control on. Toggle this button to adjust the air flow speed. To turn the rear system off, toggle the left arrow until the display turns off.