Lincoln 1997 Town Car Owner's Manual page 150

Buckling the belt.
146
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 restraint
mode). See Figure 4.
NOTE: The dual locking mode retractor must be in
the automatic locking mode to properly restrain a
child seat.