Like many, I've been frustrated with the back-up and side view camera on the Axis/Vegas. Sometimes it worked, sometimes it didn't and then just didn't. "No Signal" seemed to work perfectly on the screen. I finally fixed mine and took a few pics. My problem may have been different from others but it is now solved and proven with a 250 mile trip on some not so wonderful roads. So here goes, hope this is a help to some.
DISCLAIMER: I am not the sharpest knife in the drawer and am no engineer.
Mine looks like this. Yours might.
Two screws under the removable rubber mat
Easily removed with a #4x2 (?) screwdriver.
And then you gasp when you uncover this mess. Well, I did.
Moving the mess around I found this little thing here. The connector in my MH is yellow and black. It has a "camera" label attached. Mine was not a tight connection but quite loose. Bouncing along the highways could cause an intermittent or complete loss of signal.
Drawing on what little technical knowledge is stored in my brain I wrapped it in electricians tape after insuring it was fully connected. Honestly I would have used scotch, painters, masking, duct or whatever tape was available but the electrical was in the tool box in the MH. And a mighty fine wrap job it is.
Success! It has worked perfectly.
Hope this is helpful to someone.