Ford F-350 Owner's Manual page 75

While operating in Headphone Only Mode, the system will have limited
functionality.
• The system will only output audio to the headphones. It will not be
capable of providing audio to the speakers.
• The available sources in FES Headphone Only Mode are DVD-DISC
and DVD-AUX, regardless of headphone channel (A or B).
• When a disc is inserted into the FES while in Headphone Only Mode,
both headphone channels (A and B) will be connected to FES-DISC.
2008 F-250/350/450/550 (f23)
Owners Guide (post-2002-fmt)
USA (fus)
Entertainment Systems
75