A few months ago I successfully retrofitted a backup camera in my C6 4f - found all the parts on ebay, cost around £300 in total, not including the loom which I made myself.
Its been working perfectly up until a week or so ago -
When I select reverse I just get a blank screen where the video should be.....however, every now and again I get a broken interference picture on screen and then it disappears - I also get the guide lines which move with the steering -
There are no fault codes logged in VCDS and I can see that (according to VCDS) video signal is present - what I am trying to find out is which bit of kit overlays the tram lines onto the camera output - I thought originally that it was the camera controller (in the boot) but I have changed that and it still doesn't work - the next 'logical ' item would be the MMI controller where the video signal from the camera controller plugs into - this is a PITA to change as it contains component protection -
does anyone know if there is another controller that manages this?

Mark