That's actually a very good question that I have thought of before but don't have the answer to, but assuming some things, it could theoretically be possible. I am guessing here, but the factory backup camera might work off of an CVBS video signal type. The CVBS video signal was used for almost everything during the 2000s (Think of the yellow, white and red RCAs that you plugged into your old bulky TV). This was before the invention and widespread use of HD video signal types. If this is the case, it would just being be a matter of hooking up 2 wires. You see RCA is super simple. You have one wire that makes up the video composite and is typically yellow in color and then you have the shield wire. So all you would have to do is find those 2 video signal wires that go to the H3's OEM backup camera, and tap into them by cutting a RCA extension cable (using the male side) and soldering them to the video signal wires. From there, you can plug in your male RCA to your head unit and it should work. This is something that I have wondered about. In the future I want to try it out because I think it would actually be pretty useful.