Pontiac 2003 Bonneville Owner's Manual page 29

2.
Push the latch plate into the buckle until it clicks.
If the belt stops before it reaches the buckle,
tilt the 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 on page 1-26.
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.
3. To make the lap part tight, pull down on the buckle
end of the belt as you pull up on the shoulder part.
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