2008 Suburban.
I had cracked screen and radio wasn't working, and I've replaced the radio (same part#) and had dealer to program it. My volume was maxed out. I thought maybe volume **** doesn't work and purchased another radio, took it to a dealership for programming. Same problem: The volume is maxed out and **** doesn't work. Replaced the amplifier, and having the same problem. I paid for each programming ...
Then I found this forum ))
I believe dealer is nor programming it correctly. What should I tell them? Do they have a special update or firmware they need to use? How to explain them?

TIA