2003 bounder ford v10 no start

I need to add some more to the puzzle; There is no power at the dash when the key is turned on, ignition sw has been replaced. Horn is inop, headlights are inop, electric brake boost is inop. I have a truck tech here working on it now, but I'm not encouraged yet. Good Sam ERS insisted on sending a mobil guy out rather than tow it about 12 miles. The problem appears to be prior to the starter circuitry.
Keep the suggestions flowing and when it is finally repaired I'll post the repair!