Ford 2006 F150 Owner's Manual page 126

Seating and Safety Restraints
Insert the tongue into the correct
buckle (the buckle closest to the
direction the tongue is coming
from). To lengthen the belt, turn the
tongue at a right angle to the belt
and pull across your lap until it
reaches the buckle. To tighten the
belt, pull the loose end of the belt
through the tongue until it fits
snugly across the hips.
Shorten and fasten the belt when
not in use.
Vehicle sensitive mode
The vehicle sensitive mode is the normal retractor mode, allowing free
shoulder belt length adjustment to your movements and locking in
response to vehicle movement. For example, if the driver brakes
suddenly or turns a corner sharply, or the vehicle receives an impact of
approximately 5 mph (8 km/h) or more, the combination safety belts will
lock to help reduce forward movement of the driver and passengers.
The front outboard safety belts can also be made to lock manually by
quickly pulling on the shoulder belt. Rear safety belts (if equipped) can
also be made to lock up by pulling quickly on the belt.
Automatic locking mode
In this mode, the shoulder belt is automatically pre-locked. The belt will
still retract to remove any slack in the shoulder belt.
The automatic locking mode is not available on the driver safety belt, or
the Regular Cab center safety belt.
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