Awesome. Keep us posted. But I think you're missing a wire. You're likely going to need something that goes from the PDIM > Stereo. It's how the stereo talks to the PDIM module and controls it. As of now, your PDIM will be off in space and likely won't do anything. I don't think it will even show up as an option to switch to when you plug a USB device in. I
posted a bit of analysis of the schematics a while back. Maybe it's already there and just not connected? Or maybe I'm just wrong altogether?