Ford 1999 Explorer Owner's Manual page 136

Seating and safety restraints
Installing child safety seats in combination lap and shoulder belt
seating positions
1. Position the child safety seat in a
seat with a combination lap and
shoulder belt.
An air bag can kill or injure a child in a child seat. If you must
use a forward-facing child seat in the front seat, move seat all
the way back.
Children 12 and under should be properly restrained in the rear
seat whenever possible.
2. Pull down on the shoulder belt
and then grasp the shoulder belt
and lap belt together.
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