Is the rear camera of your dashcam no longer working (properly)? This could have several causes. Follow these steps to solve the problem.
Check recordings It is important to first check whether it is actually not recording. To do this, first check the recordings on the SD card to see if the rear camera is no longer recording. On some dashcams with LCD screens, only the front camera is displayed in the picture by default and a button can be used to switch between the front and rear camera. It may then appear that the rear camera is not connected properly or no longer works.
Check the connection Are there no recordings from the rear camera on the SD card? Then chances are there is something wrong with the plugs or cable. Disconnect all connectors of the front and rear camera to make sure it is not because of one of the connectors.
Rear camera replacement Are there videos from the rear camera on the SD card but are not good or do you have a black image? Then there is probably something wrong with the rear camera. Contact the selling party for a suitable solution, often only the rear camera needs to be replaced.
With many dashcams, the rear camera is connected to the long cable to the dashcam on the windscreen with a connector. In that case, you can first disconnect the connector and replace just the camera, hopefully avoiding the need to replace the entire cable. If that still doesn't fix the problem, the cable may need to be replaced.
See this article for how to connect the rear camera correctly. If you mount the camera outside, for example, it is important to make a loop under the camera so that water does not accumulate in the lens.