GMC 2001 Sierra 1500 Pickup Owner's Manual page 17

Move the seat forward or rearward by moving the whole
button toward the front or toward the rear of the vehicle.
Moving the whole button up or down raises or lowers
the entire seat cushion.
Vertical Control: If your vehicle has power reclining
seats, you can use this button to adjust the angle of the
seatback. Move the reclining front seatback rearward or
forward by moving the button toward the rear or toward
the front of the vehicle. See "Reclining Seatbacks" in
the Index for further information.
Power Lumbar Control (If Equipped)
1-4
If you have power
lumbar adjustment, you
can increase or decrease
lumbar support in an area
of the lower seatback.
The control is located on
the on outboard of the
cushion seat.
To increase support, press and hold the front of the
control. Let go of the control when the lower seatback
reaches the desired level of support.
To decrease support, press and hold the rear of the
control. Let go of the control when the lower seatback
reaches the desired level of support.
You can also reshape the back wing area of the
lower seatback.
To increase support, press and hold the top of the
control. Let go of the control when the lower seatback
reaches the desired level of support.
To decrease support, press and hold the bottom of the
control. Let go of the control when the lower seatback
reaches the desired level of support.