In reference to Mike's question:
"Does it automatically switch the view (from whatever is displayed) to the side cameras when the turn signals are used?"
Does this functionality exist in the stock video units -- In my case the Kenwood KVT-M700? I never used that head-unit for radio functions and therefore do not know whether the unit automatically changed from Radio control screen to video camera view when the turn signals are enabled.
I can say this.... the KVT-M700 does not seem to have a trigger wire that would signal the unit that the coach turn signals are on or even if the coach is in reverse. This is common in new head units but it does not look like that is built into the old head unit.
I suspect that all control regarding switching to camera views (left, right or back) is through the Aladdin system. In other words, if you are viewing Aladdin information on the screen then switching between cameras is handled by the Aladdin and therefore those changes can be viewed on the screen. If however, the radio is on a different source than the Aladdin then I don't see a way to signal the radio to switch views.
That could happen by sending a second video signal to the "back-up camera" video source... but then the problem becomes... what triggers that? Probably easy to trigger off of the back-up lamp circuit... not not sure how to trigger off of the backup lamp circuit and the turn signal circuit. Any ideas on how to accomplish that?