GMC 1998 Safari Owner's Manual page 47

Lap-Shoulder Belt
These positions have lap-shoulder belts. Here's how to
wear one properly.
1. Pick up the latch plate and pull the belt across you.
2. Push the latch plate into the buckle until it clicks.
Don't let it get twisted.
If the belt is not long enough, see "Safety Belt
Extender" at the end of this section.
Make sure the release button on the buckle is
positioned so you would be able to unbuckle the
safety belt quickly if you ever had to.
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