GMC 2001 Savana - Manual (Page 31)

1-18
Shoulder Belt Height Adjuster
Before you begin to drive, move the shoulder belt
adjuster to the height that is right for you.
To move it down, push in at the top of the arrows and
move the height adjuster to the desired position. You can
move the adjuster up just by pushing up on the shoulder
belt guide. After you move the adjuster to where you
want it, try to move it down without pushing in to make
sure it has locked into position.
Adjust the height so that the shoulder portion of the belt is
centered on your shoulder. The belt should be away from
your face and neck, but not falling off your shoulder.