Got this A4 a few months ago. Did a heater core change and now putting it back together.The car has a different HU and some sloppy wiring job. I have been searching and looking for a wire diagram. I am just trying to figure out what wire goes where and the colors. It has the factory bose amp in the rear but looks like it was bypassed. Not sure if the rear speakers are factory but were not hooked up. The radio did work but the balance and fader controls did not work properly. It appears the original ISO plugs are still intact and they used a adapter to hook to them. If anybody can help or share any info it would be greatly appreciated.

Thanks,
John