No 12V Chassis Power

2000 Pace Arrow Vision.  I suddenly have no power to the chassis; no start, no lights, no steps.  Battery voltage, after not being used for several weeks, measures 12.1 V.  Suspected loose battery cable; tried jumping from another vehicle, nothing.  Suspected a malfunction in the power center up front; turning power switch inside on and off, I hear the "clunk" moving the solenoid inside the power center, still nothing.  If  there is another fuse or switch to check, I don't know where to look.  Any help would be appreciated.