I'm trying to work out the right way to wire in a Kenwood reversing camera to a Kenwood head unit in my Mk5 Legacy wagon. The harness which comes with the camera has an easy plug connection at the camera end then a yellow plug and two bare wires, red and black at the other end. The yellow plug goes into the appropriate socket at the back of the unit but then I get confused. Also coming out of the back of the head unit is a short wire labelled "reversing sensor". The camera needs power and the head unit needs to know when I select reverse - which wire goes where? 

surely the red is12v supply  and the black is earth/ground ?

Without seeing the kit itself I believe shms to be correct.

The wire labelled as reversing sensor should take a 12v feed from your reversing light cct this tells that head unit that you have selected reverse

You could also wire the red to the same cct or have a switch on the dash

Black is ground / earth

http://www.manualsdir.com/manuals/412138/kenwood-kvt-524dvd.html?page=4