Based on the information provided by @Mikescotland, I have attempted to draw a connection.
Plug in CAR to DUDU:
Speakers:
A2 Right Front + --> G11
A3 Left Front + --> G15
A6 Right Front - --> G9
A7 Left Front - --> G13
Power:
A12 12v battery --> G2
A16 GND --> G1 or A9 GND --> G1
B1 12v ACC --> G3
B7 ILLUMNI --> G4
If I understand correctly, the B7 Illumin should only have 12V when the car lights are on, so check the voltage with the lights off and on.
Of course, please double check it!
