If your vehicle is showing backup camera screen is completely black or heavily distorted, here are the most likely causes and the parts you'll need to fix each one.
Weather seals on the exterior camera can degrade over time, allowing moisture inside that shorts the internal electronics or permanently damages the image sensor.
The wiring harness that bends every time you open the trunk or liftgate can fatigue and break over time, severing the video feed or power connection to the camera.
If an aftermarket radio or camera was recently installed, the RCA video cable behind the dashboard or the camera's ground wire in the trunk may be loose, pinched, or poorly crimped.
The backup camera often shares a power circuit with the reverse lights. If a bulb shorts out or the circuit overloads, the blown fuse will cut power to the camera, resulting in a black screen.
The vehicle's main display screen or internal video processing module has failed and can no longer process or display the incoming video signal.