Rear camera not coming on says take to dealership?

The system looks pretty basic. There is a camera and an Accessory Protocol Interface Module (APIM) I would replace the camera because these go out all the time. You might be able to find a used one at an auto wrecker or Ebay to save some money. Here are the wiring diagrams so you can see how it works. Also, you can do a CAN scan to see what else might be wrong, this is what the dealer will do. You can get a CAN scanner from Amazon for about $30.00.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here is a scanner link:

https://amzn.to/3o41KcZ

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.