Chevrolet 2003 Tahoe Owner's Manual page 46

2. Push the latch plate into the buckle until it clicks.
Pull up on the latch plate to make sure it is
secure.
When the shoulder belt is pulled out all the way, it
will lock. If it does, let it go back all the way
and start again.
If the belt is not long enough, see Safety Belt
Extender on page 1-43.
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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