I have a Golf 7 Comfortline 2014, that came with no reversing camera. So I found a near new Highline that was being wrecked and got the emblem reversing camera, the Sat Nav CD player, the Head Unit and the wiring loom. After fitting them all, the camera looked like it would work but it had a black screen (It does work as I tried it on a friends GTI). The Sat Nav mostly worked but had the " component protection line on it and the CD player ws muted.

I took it to the dealer and they handed it back with the sound working but no Nav and no camera. They said that because it was not in the car from new the coding wiped it

Anyone know what I/they should be doing?