The solution is as follows:
If the display screen is damaged, even if our camera is normal, there is no way to display normal images. In this case, we need to replace the new display screen.
If the wiring in the car is not in good contact, the image will not be displayed when we reverse. At this time, we need to go to the 4s shop and ask professionals to help us repair the wiring.
If we use inferior cameras, or the cameras are used for too long, the internal chips will be damaged. Therefore, when we reverse the car, the reverse image will not show the image. We need to go to the 4s shop or the repair shop outside to replace the new camera, which can solve the problem.