Ford F series Owner's Manual page 128

5. Grasp the shoulder portion of the belt and
pull downward until all of the belt is
extracted and a click is heard. At this time,
the retractor is in the automatic locking
mode (child seat restraint mode). See
Figure 4.
NOTE: The dual-locking mode retractor must
be in the automatic locking mode to
properly restrain a child.
Setting the retractor to automatic locking mode
6. Allow the belt to retract. Pull up on the
shoulder webbing. A clicking sound will be
heard as the belt retracts. This indicates the
retractor is in the automatic locking mode.
Push down on the child seat while you pull
up on the belt to remove any slack in the
belt. See Figures 5 and 6.
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