Yes, the MultiPlex is more complex, but has its advantages. Admittedly, it still manages to confuse me when something goes awry occasionally, but its certainly more sophisticated than Goldberg's contraptions.
You can have many "switches" on one relatively small plate compared to standard toggle ones. When you tap one, all proximal buttons backlight so that in dim light you can see which one you really want to press; that's not the case for example if when entering a dark coach you've tried to remember which of the dark toggles in the long row by the door is the right one. Many Multiplex touch buttons control dimmable lights so multiple presses or holding of a button will cycle up and down through dimmer levels. A dimmed light will retain that point at turn off and come back on next time at the same level. There is a Master bedside switch that will turn off any MultiPlex lighting left on in the coach. These are features of a system with a central control.
Except perhaps for low current button backlighting, the only significant positive/ground 2-wire configuration is at the Multiplex control and fuse location in the cabinet above your toilet, conveniently located with other house 12 volt fuses and your two alternating current (120v) Main and Inverter breaker boxes. Each pressable Multiplex button feeds information (such as number of presses or length of time held) to that controller via a single data transmission wire, and the controller is like a computer that interprets that data and responds by powering a 12 volt light or device accordingly. The controller also is where a dimmed light's level is remembered for next time. Because there is minimal moving parts, touch-button switch plates don't exhibit wear and are relatively trouble free, one reason I didn't think you needed to risk breaking into yours. If each press button had to have two wires like a standard switch, that's twice as many long-routed wires and connections to go haywire, Roger.
So yeah, it is more complicated, but it offers more convenient device control and is less likely to quit on you. Yours did, but only because you inadvertantly short-circuited something. Yours is a model coach similar to mine, so I'd make a fuse list and tape it in the cabinet like in the photo I supplied, so next time you know which fuse is involved. You can remove fuses one at a time I guess and check switch operations to verify for sure that your fuses match my list.
Joel
