Ford 2009 Expedition Owner's Manual page 64

Entertainment Systems
Headphones
Wireless headphones
WARNING: The driver should never use the headphones while
driving the vehicle. Using headphones may prevent the driver
from hearing audible warnings such as horns or emergency sirens,
which could result in a crash causing serious injury. Give your full
attention to driving and to the road.
Your FES system is equipped with
two sets of battery powered,
infrared wireless headphones. Two
AAA batteries are needed to operate
the headphones. (Batteries are
included.)
Additional infrared wireless
headphones may be purchased for
use with the system. Also, wired
headphones may be purchased and
plugged in where indicated on the
left and right hand sides of the
system. Refer to Wired
Headphones following.
64
2009 Expedition (exd)
Owners Guide, 1st Printing
USA (fus)