You can download a soft copy of your owners manual here:
https://www.monacocoach.com/rv-owners-manuals
This makes it easy to do word searches in Adobe Acrobat.
From page 168 of your owners manual:
The “Master Off” switch is located on a
multiplex panel above the copilot seat. The
setting of dimmable lights will be retained
after turning the lights off and back on.
Press and release to turn on and off all
multiplex switch backlighting.
Press and hold the switch for three
seconds to turn off all interior
multiplexed lighting.
Press and hold the switch for six
seconds to turn on all interior
multiplexed lighting. Continue holding
the switch and the living area lights
will turn off followed by all remaining
multiplex lights.
Continue holding the switch for the
appropriate amount of time after any
operation to turn lighting back on or
off.
Hope this helps.