Cadillac 2000 DeVille Owner's Manual page 28

4. Now you can add a small amount of slack. Lean
forward slightly, then sit back. If you've added more
than 1 inch (25 mm) of slack, pull the shoulder belt
out as you did before and start again.
If you move around in the vehicle enough, or if you pull
out the shoulder belt, the belt will become tight again. If
this happens, you can reset it.
CAUTION:
For many people, it takes two hands to adjust the
shoulder belt for tightness because a lot of
webbing must be pulled out. If you ever tried to
do this while driving, you could lose control of the
vehicle. Adjust your shoulder belt for tightness
only when your vehicle isn't moving.
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