Back up camera trouble

There is a 3-way controller on my rig. One video display (now JVC), with two side cameras and one back-up camera. The 3 to 1 controller is a white plastic gizmo under the video head, with a 12v power input, three video in, one out.
HTH

My rear camera would stop working and intermittingly work for a bit and then stop again. Dealer first replaced wiring harness which seemed like a good start. I swore it was a bad ground. No joy. Same symptoms. Then they replaced screen in the dash. I didn't figure that was the issue...nope, same issue. Finally just replaced camera, and that fixed it. unsure if this is typical or what model camera it is. This is a 2018 Tiffin Allegro RED coach.

Whenever my camera stops working it's because the radio/display switch to 'see' the camera is off. That happens if the batteries are disconnected for any reason.