I suspect you have a problem in the wiring harness. It could be a loose connection. Recommend you remove camera and access connection, unfasten, clean connections with electronic turner cleaner and reconnect. Do the same on the front connections at the monitor. Test drive and determine results. Lets us know.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7