I have a 12VDC Fuse Panel under my drivers seat, on the outboard side, that is not from M-B. And I can't find any reference to it in the FR documentation that came with our 2400W. To make it more "fun" there is no labeling for any of the fuses! Do you have any documentation on this fuse panel? I suspect it is the panel FR installs for the coach exterior lighting.
On a related note bclemens posted the wiring diagrams for most of the MBS floor plans awhile back. That was prior to the "W" being released. Would you mind checking to see if we could get the "W" wiring diagrams posted as well please....