GMC Sierra 2000 Owner's Manual page 40

2. Push the latch plate into the buckle until it clicks. 3. To make the lap part tight, pull down on the buckle
If the belt stops before it reaches the buckle, tilt the end of the belt as you pull up on the shoulder part.
latch plate and keep pulling until you can buckle it.
Pull up on the latch plate to make sure it is secure.
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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