FORD 1999 F-350 - Manual (Page 51)

Your audio system is equipped with selective lighting, a unique lighting
strategy. This lighting feature is operable when the headlamps are
illuminated. During the operation of any selected mode, lighting for the
individual function controls will either illuminate or turn off. Those
controls which have a function for the specific mode of operation
selected will be lit, while the controls which have no function for that
mode will be turned off.
Volume/power control
Press the control to turn the audio
system on or off.
Turn control to raise or lower
volume.
If the volume is set above a certain level and the ignition is turned off,
the volume will come back on at a “nominal” listening level when the
ignition switch is turned back on. If you wish to maintain your preset
volume level, turn the audio system off with the power control before
switching off the ignition.
AM/FM select
The AM/FM select control works in
radio, tape and CD modes.
VOL - PUSH ON
VOL - PUSH ON
AM FM
Controls and features
51