Pioneer MVH-AV270BT Operation Manual page 24

System settings
vehicle's headlights are off (daytime) and on
(nighttime).
 "Brightness" and "Contrast" are switched auto-
matically depending on whether the vehicle's
headlights are on or off.
 "Dimmer" can be changed the setting or the time
to switch it to on or off.
 Setting the dimmer on page 23
 The setting contents can be memorized
separately.
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