GMC 2003 C4C042 Owner's Manual page 9

Seats and Seat Controls
This section tells you about the seats in your vehicle and
how to adjust them. It also tells you about reclining front
seatbacks.
CAUTION:
You can lose control of the vehicle if you try to
adjust the seat while the vehicle is moving. The
sudden movement could startle and confuse you,
or make you push a pedal when you don't want
to. Adjust the driver's seat only when the vehicle
is not moving.
1-2
Bucket Seats (If Equipped)
If your vehicle has bucket seats, also known as static
seats, you can adjust them forward or rearward with the
lever located at the front of the seat.
To adjust the seat, pull the lever up to release the seat
bottom. Slide the seat to where you want it and release
the lever. Then try to move the seat with your body, to
make sure the seat is locked in place.