It may be your only fix is to install a complete new system, including rear camera, cable from the camera to the monitor, and monitor. A high res camera and color monitor are a great improvement.
2004 Flair 33R, 336 watts solar, Dometic Sidewise frig. Pan hard bars, front and rear, CHF, Timbrens front and rear, Roadmaster reflex steering dampener. Doug Thorley Tri-y headers, small tune.