Chevrolet 2012 Tahoe Owner's Manual page 118

3-62 Seats and Restraints
For third row seating positions,
with cinching latch plates, tilt the
latch plate to adjust the belt if
needed.
3. Push the latch plate into the
buckle until it clicks.
Position the release button on
the buckle so that the safety belt
could be quickly unbuckled if
necessary.
4. For passenger seating positions
with a lap shoulder belt and a
free falling latch plate, pull the
rest of the shoulder belt all the
way out of the retractor to set
the lock. When installing a child
restraint using a lap shoulder
belt and a cinching latch plate,
skip Step 4 and proceed to
Step 5.