Melbourne 29D: how to operate Clarion stereo when parked?

[Davidvl]

The Jayco factory installed Clarion NX501 in dash multi-media stereo etc will not operate if parked when: ignition is in "Accessory" position; "Off" position; Battery Disconnect is engaged or not; Emergency brake is engaged or not. In any of the foregoing there seems to be no power reaching the Clarion unless the ignition is in the "On" position. Ours is a 2014 Ford E-450 gas chassis on which is built a Jayco Melbourne 29D coach which was part of a rental fleet until we bought it recently and wonder if the fleet operator disabled the ability of the Clarion to operate unless the ignition is on.
Any suggestions would be welcomed, with thanks,
David & Joanne

[WaltW]

if your Melbourne is wired anything like my Seneca the radio should operate with either the ignition switch in the ON position or with the house 12V turned on. Maybe there's a fuse in the house line that's bad?