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.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL