GMC YUKON DENALI 1999 Owner's Manual page 22

Shoulder Belt Height Adjuster
Before you begin to drive, move the shoulder belt
adjuster to the height that is right for you.
1-16
To move it down, push in at the word PRESS 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.
yellowblue