I'm trying to retrofit navi in my BMW E39. I have a "afterwards-cable" of Kufatech.de (e-bay).

The folowing problems occurs;
When everything is fitted the screen starts, radio works (BM24, volume settings are possible and tune to another station) with the logo === BMW ===.

But the system doesn't start any further. When I unplug the MK3, I should get the interface of the TV-module. But that doesn't do a thing.
The screen stays completely white, nothing happens. Even after a 10 minute break (for us, coffee, a sigaret, and some stress )

I tested the videomodule in another BMW (3 E46 with navi) and that was working all right.

Does anybody knows what this could be?