It appears your Clarion's display is set up to receive inputs from side and rear vision cameras. Is your Melbourne supposed to be equipped with those? I don't think they are standard but they could well be options on yours. If you aren't sure if you have them, check with the selling dealer.
In a rig equipped with them, the appropriate side camera comes on when the turn signal is activated and the rear camera when in reverse.
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL