The simulated flames are produced by rotating an object composed of strips of foil in front of a bunch of lights and getting reflections on a mirrored surface. So there are lights that need to be on that are switch controlled. These lights do also burn out. If the switch is on for the lights and the system isn't working, then you have to pull and disassemble the unit to find out the failure mode.
2012 F350 6.7 L dually, 2013 3800RE with 6 pt leveling, Sumitomo 17.5" load range h tires, Samsung 18 cu ft residential fridge, 8k Morryde I.S. with disc brakes. Full timing since 2012.