GMC 2003 Yukon Owner's Manual page 66

In order to use the LATCH system in your vehicle, you
need a child restraint designed for that system.
To assist you in locating the lower anchors for this child
restraint system, each seating position with the
LATCH system has a visible metal anchorage point in
the seat where the seatback meets the seat cushion.
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CAUTION:
If a LATCH-type child restraint isn't attached to
its anchorage points, the restraint won't be
able to protect the child correctly. In a crash,
the child could be seriously injured or killed.
Make sure that a LATCH-type child restraint is
properly installed using the anchorage points,
or use the vehicle's safety belts to secure the
restraint. See "Securing a Child Restraint
Designed for the LATCH System", "Securing a
Child Restraint in a Rear Outside Seat
Position", "Securing a Child Restraint in a
Center Rear Seat Position", "Securing a Child
Restraint in the Center Front Seat Position" or
"Securing a Child Restraint in the Right Front
Seat Position"in the Index for information on
how to secure a child restraint in your vehicle.