Ford 1999 Wagon-Econoline Owner's Manual page 35

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 the 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.
Speed sensitive volume (if equipped)
With this feature, radio volume changes automatically and slightly with
vehicle speed to compensate for road and wind noise.
The recommended level for speed sensitive volume is from level 1
through level 3. Level 0 turns the speed sensitive volume off and level 7
is the maximum setting.
With the radio on, press and hold
the volume control for five seconds,
then press:
Controls and features
VOL
PUSH ON
VOL
PUSH ON
VOL
PUSH ON
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