Hello to the community, I have unfortunately little experience with forums, but try nevertheless my luck. Here my problem, my wife has gained a used Seat Arona Referenc year 2019. He has only installed the touchscreen (radio) with 4 speakers front, that was my Holden a little too little sound. She also had loudspeakers installed in the rear doors from an audio workshop, via the diagnostic plug the fader function was unlocked and can also be operated. Unfortunately, no sound comes from the rear speakers, the audio workshop tried again to configure the audio system with a laptop….kei success. Has someone a tip or experience with it, I am grateful for every answer.