Well, regarding the sat nav, I pulled the the navigation unit halfway out it's retaining "cage" in the boot, I did this in order to be able to move the black boot wall cover for finding a good earth connection for the amp, maybe I disconnected a connector behind the sat nav that also has to do with this k bus system? I really have no idea, hence my question, actually I have never ever used the original sat nav of the car, never put a cd in it and was also never able to turn it on because on my old symphony unit the buttons for the sat nav were dead... Will try my luck tomorrow for the connectors under the seat and disconnecting the amp and the battery again for half an hour, thanks for now! I'll come tomorrow back here with an answer