Ford 1999 Explorer Owner's Manual page 61

Controls and features
Turn control to raise or lower
VOL - PUSH ON
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
AM FM
radio, tape and CD modes.
AM/FM select in radio mode
This control allows you to select AM or FM frequency bands. Press the
control to switch between AM, FM1 or FM2 memory preset stations.
AM/FM select in tape mode
Press this control to stop tape play and begin radio play.
AM/FM select in CD mode
Press this control to stop CD play and begin radio play.
Tune adjust
The tune control works in radio or CD mode.
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