2003 GMC Envoy Owner's Manual - Page 10

Heated Seats 1 Your vehicle may have heated front seats. The buttons used to control this feature are located on the front door armrests. The engine must be running for the heated seat feature to work. To heat the entire seat, press the horizontal button with the heated seat symbol. Press the button repeatedly to cycle through the temperature settings of high, medium, low and off. The indicator lights will glow to designate the level of heat selected: three for high, two for medium and one for low. The low setting warms the seatback and cushion until the seat temperature is near body temperature. The medium and high settings heat the seatback and seat cushion to a slightly higher temperature. You will be able to feel heat inabout two minutes. To heat only the seatback, press the button with the words "BACK ONLY". An indicator light on the seatback switch will glow to designate that only the seatback is being heated. Additional presses will cycle through the heat levels for the seatback only. Press the horizontal button again to heat the whole seat. The feature will shut off automatically when the ignition is turned off.