1998 GMC Suburban Owner's Manual - Page 16

Heated Front Seats(If Equipped) Reclining Front Seatbacks The control for the driver's side heated seat is located on the left side of the seat. The control forthe right front passenger is located on the right side of the passenger seat. Move the switch forward to MED or HIGH temperature to turn on the heating elements in the seat, The right front passenger's safety belt must be buckled before the heating elements in that seat will operate. To turn the heated seats off, move the switch rearward to OFF. To adjust the seatback, move the lever rearward. Release the lever to lock the seatback where you want it, Move the lever again rearward and the seatback will go to an upright position.