1997 GMC Suburban Owner's Manual - Page 14

Power Lumbar Adjustment(If Equipped) If you have power lumbar adjustment, you can increase or decrease lumbar support in an area of the lower seatback. Reclining Front Seatbacks To increase support, press and hold the front of the rocker switch. Let go of the switch when the lower seatback reaches the desired level of support. 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. To decrease support, press and hold the rear of the rocker switch. Let go of the switch when the lower seatback reaches the desired level of support. 1-4