If your camera works by manually turning it on but not in Reverse, your radio has to be set to wrong camera polarity. Mine does just that if my polarity is set to ground rather than battery. Take a multimeter and test your camera output. As of rear monitor, I spent a week trying to figure it out, but it also has to be the the setting in your HU. I got mirroring option and dual zone option. Does your radio support dual zone? Well, regardless of dual zone, rear video should work you just won't be able to listen to music on HU while watching a movie in the back if you don't have dual zone. What i did, i took my little tv to the car and tested rear video output. I knew that TV should work 100% if there is an output so this gave me an ability to troubleshoot and i came to realization that it was HU setting