Ford 1998 Ranger Owner's Manual page 43

2–door SuperCab
4–door SuperCab
To lower the shoulder belt height, push the button and slide the height
control down. To raise the height of the shoulder belt, slide the height
adjuster up. Pull down on the height adjustment assembly to make sure
it is locked in place.
Position the shoulder belt height adjuster so that the belt rests
across the middle of your shoulder. Failure to adjust the safety
belt properly could reduce the effectiveness of the safety belt and
increase the risk of injury in a collision.
Seating and safety restraints
43