If, and it's a big IF, you had a coffee maker on an aircraft AND it was controlled by a push button switch in the overhead panel, a "Dark Cockpit" would probably give you the following switch captions "OFF" - blank, "Fault" - Amber, "ON" blue or green. If you also had EICAS or similar, there would be no status for OFF or ON, but a fault would generate a message like "COFFEE MAKER FAULT" with a single or double chime.
If it was an Embraer E-Jet and controlled by a rotary switch, it would probably have two positions, OFF and AUTO. Moving the switch to OFF would generate and EICAS message of "COFFEE MAKER SW NOT AUTO". There would also be some perverse logic about flight level, minutes in the cruise, toilet door locks and cabin lights to make the bloody thing work, except on Wednesdays.
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