FORD 2009 F-550 v.1 - Manual (Page 61)

Battery replacement
Batteries are supplied with the remote control unit. Since all batteries
have a limited shelf life, replace them when the unit fails to control the
DVD player.
Remove the screw and unlatch the battery cover to access the batteries.
The remote control unit uses two AAA batteries which are supplied with
the unit.
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.
2009 F-250/350/450/550 (f23)
Owners Guide, 1st Printing
USA (fus)
Entertainment Systems
61