GMC 1999 Sierra 1500 Pickup Owner's Manual page 59

6. To tighten the belt, pull its free end while you push down on the child
restraint.
7. Push and pull the child restraint in different directions to be sure it is
secure. If the child restraint isn't secure, turn the latch plate over and
buckle it again. Then see if
it
is secure. If it isn't, secure the restraint in
a different place in the vehicle and contact the child restraint maker for
t
hei r advice.
To remove the child restraint, just unbuckle the vehicle's safety belt.
It
will be
ready to work for an adult or larger child passenger.
Securing a Child Restraint in the Center Seat Position
(Extended Cab)
I
PO700
You'll be using the lap belt. See the earlier part about the top strap
if the
child restraint has one.
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