If you have a reverse camera in your car that is not working, there are a few things that you can do to try and fix the issue. First, check to see if the camera is properly plugged in to the power source. If it is not, then plug it in and turn on your car to see if the camera turns on. If it does not, then you may need to replace the fuse for the camera. Another thing that you can try is to reset the system by disconnecting the battery for a few minutes and then reconnecting it. Finally, if none of these things work, you may need to replace the reverse camera itself.