GMC SIERRA 1994 Manual page 38

Lap-Shoulder Belt
The positions next to the windows have lap-shoulder belts. Here's how to
wear one properly.
L
1. Pick up the latch plate and pull the belt across you. (On some models,
you may hear a clicking sound as the belt is pulled out. The clicking
sound is the shoulder belt tension feature operating properly.) Don't let
the belt get twisted.
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" 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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