Ford 2009 F-150 Owner's Manual page 158

Seating and Safety Restraints
Properly adjust the head restraint so that the top of the head restraint is
even with the top of your head and positioned as close as possible to the
back of your head. For occupants of extremely tall stature, adjust the
head restraint to its full up position.
WARNING: The adjustable head restraint is a safety device.
Whenever possible it should be installed and properly adjusted
when the seat is occupied.
To remove the adjustable head restraint, do the following:
1. Pull up the head restraint until it
reaches the highest adjustment
position.
2. Simultaneously press and hold
both the adjust/release button and
the unlock/remove button, then pull
up on the head restraint.
158
2009 F-150 (f12)
Owners Guide, 2nd Printing
USA (fus)