Aftermarket stereo Issue
 

I had a Pioneer AVH-4200NEX installed recently. The shop is having issues getting the USB sync working proper. They have most of the bugs except the fader is nonoperable. Has anyone had this issue? I'm trying to find a solution for them. On the plus, the system uses Android Auto to link your smartphone.

Finally reached a live person with the company that made the USB link. The up/down buttons on the steering wheel is now the stereo fader. That actually works!