FYI, if you have mirror mounted cameras, they are from another manufacturer ASA Electronics. RVS system has proprietary cables and the ASA side cameras have an extra rewired cable so as to connect with the RVS system. It's between the end of the mirror camera cable in the arm and runs to the multiplexer.
Also, have you tried adjusting the brightness and contrast? Also, read the manual about doing a system reboot by disconnecting the power cable for a while.
Good luck and please keep up posted as others may have the same issue in the future.
2004 Winnebago Minnie 22e(went to a nice family Oct 3, 2015)
2016 Forester 2701DS (Aug 31, 2015)
2017 Camping 2 trips 5 nights