Ford 2009 F-150 Owner's Manual page 186

Seating and Safety Restraints
seat cushion, with their feet comfortably extended on the floor. Sitting
improperly can increase the chance of injury in a crash event. For
example, if an occupant slouches, lies down, turns sideways, sits forward,
leans forward or sideways, or puts one or both feet up, the chance of
injury during a crash is greatly increased.
WARNING: Sitting improperly out of position or with the seat
back reclined too far can take off weight from the seat cushion
and affect the decision of the front passenger sensing system, resulting
in serious injury or death in a crash.
Always sit upright against your seatback, with your feet on the floor.
The front passenger sensing system may detect small or medium objects
placed on the seat cushion. For most objects that are in the front
passenger seat, the passenger airbag will be disabled. Even though the
passenger airbag is disabled, the pass airbag off lamp may or may not
be illuminated according to the table below.
Objects
Small (i.e. three-ring
binder, small purse,
bottled water)
Medium (i.e. heavy
briefcase, fully packed
luggage)
Empty seat, or small
to medium object with
safety belt buckled
In case there is a problem with the
front passenger sensing system, the
airbag readiness lamp in the
instrument cluster will stay lit.
DO NOT attempt to repair or service the system; take your vehicle
immediately to an authorized dealer.
WARNING: The front passenger airbag is not designed to offer
protection to an occupant in the center seating position.
186
2009 F-150 (f12)
Owners Guide, 2nd Printing
USA (fus)
Pass Airbag Off
Indicator Lamp
Unlit
Lit
Lit
Passenger Airbag
Disabled
Disabled
Disabled