Before I sadly got rid of my A3 saloon (2014) with the Audi Sound System, I had the MIB unit repaired at Revtronic Bradford (https://www.revtronic.com/product/audi-a3-8v-a4-harman-mib-no-sound-cutting-out/), I'm not endorsed by them in any way but I disconnected the unit, sent it away and had it...