It's kind of a funny story with the Subaru. We have an '06 Outback XT with factory navigation. The back-up camera was never an option for the Outback in that model year, and yet everything was wired and ready for a camera. Some dude was sharp enough to recognize the plug in the back of the nav screen and figure out the pins. The homemade harness was easy enough to make, so plugging in an RCA jack makes the connection universal. Then you just need power and ground, and you're done!