Ford F-150 2010 Owner's Manual page 177

2. Grasp the shoulder portion and
pull downward until the entire belt
is extracted.
3. Allow the belt to retract. As the belt retracts, you will hear a clicking
sound. This indicates the safety belt is now in the automatic locking
mode.
How to disengage the automatic locking mode
Disconnect the combination lap/shoulder belt and allow it to retract
completely to disengage the automatic locking mode and activate the
vehicle sensitive (emergency) locking mode.
WARNING: After any vehicle collision, the safety belt systems
at all seating positions (except the driver position, which does
not have this feature) must be checked by an authorized dealer to
verify that the automatic locking retractor feature for child seats is still
functioning properly. In addition, all safety belts should be checked for
proper function.
WARNING: BELT AND RETRACTOR ASSEMBLY MUST BE
REPLACED if the safety belt assembly "automatic locking
retractor" feature or any other safety belt function is not operating
properly when checked by an authorized dealer. Failure to replace the
Belt and Retractor assembly could increase the risk of injury in
collisions.
Safety belt pretensioner
Your vehicle is equipped with safety belt pretensioners at the driver and
right front passenger seating positions.
The safety belt pretensioner removes some slack from the safety belt
system at the start of a crash. The safety belt pretensioner uses the
same crash sensor system as the front airbags and Safety Canopy
System. When the safety belt pretensioner deploys, the lap and shoulder
belt are tightened.
Seating and Safety Restraints
177