Pontiac 2003 Montana Owner's Manual page 89

You'll be using the child restraint's harness (A) to
secure your child. Don't use the vehicle's safety
belts.
Using the vehicle's regular safety belts on a
child seated
on
the child restraint cushion can
cause serious injury to the child in a sudden
stop or crash. If a child is the proper size for
the built-in child restraint, secure the child
using the child restraint's harness. But
children who are too large for the built-in child
restraint should sit on the vehicle's regular
seat and use the vehicle's adult safety belts.
Warning: Failure to follow the manufacturer's
instructions on the use of this child restraint system can
result in your child striking the vehicle's interior during
a sudden stop or crash. Snugly adjust the belts provided
with this child restraint around your child.
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