[AudiA4B6US]

D: Power Connector
9 - CAN-H ------------------------------------ Free wire to connect to infotainment canbus-H
10 - CAN-L ----------------------------------- Free wire to connect to infotainment canbus-L
11 - TEL-Mute ------------------------------- Connector 3 – Tel Mute – Pin 2
12 - Kl.31 (Masse)
13 - U14 ST DSP (radio On)
14 - DWA-GND
15 - Kl.30 ------------------------------------ Connector 3 – GND – Pin 8
16 - U14R-1 ---------------------------------- Connector 3 - +12V – Pin 7

Can you confirm that you connected D15 (KL 30) to ground and D16 (U14R-1) to 12V+? I think D12 (KL 31) is ground and D15 (KL 30) is 12V+.