Well, it is even simpler (or worse...): I do not have a wire in the RNS-E quadlock connector B pin 5... I do not even have a connector B...
Where should I go from here? Buy a new adapter? How can I be sure it is the right one this time ? Have a European 2003 Audi S4 (B6), a Concert radio (single to double din conversion almost done), Bose Sound System and a 8E0 035 192 D RNS-E.