Audi a3 07 8pm sports back. I have fitted a pioneer double din head unit. Bought a reverse camera to fit to the head unit. Test wired everything +12v to the power for the reverse light same for the grounding wire(ground for he reverse light) Ran a wire through the car to the reverse signal in the back of the head unit so the camera screen pops up automatically when reverse is engaged. And obviously the a/c output into the a/c input of the headunit. Everything worked perfect so I hid all the wires replaced all the trim. I then started the engine to give the camera it's first real test an I got a very fussy interfered with picture and the automatic pop up didn't engaged I had to physically chose the camera mode. Has anyone got any ideas on what could be the issue here? Thanks Bryan.