GMC 2003 Savana Van Owner's Manual page 23

The lap part of the belt should be worn low and snug on
the hips, just touching the thighs. In a crash, this
applies force to the strong pelvic bones. And you'd be
less likely to slide under the lap belt. If you slid under it,
the belt would apply force at your abdomen. This
could cause serious or even fatal injuries. The shoulder
belt should go over the shoulder and across the
chest. These parts of the body are best able to take belt
restraining forces.
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, pull on
the center adjuster control
labeled PULL. You can
move the adjuster up just
by pushing up on the
shoulder belt guide.
After you move the adjust€. 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.
The safety belt locks if there's a sudden stop or crash.
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