Do any of you guys know how to unlock a Silverado/Sierra radio. I upgraded my head unit in my '06 HD and gave it to my dad for his HD. His took a crap. We plugged it all in, but it says "locked". I was told by the shop that there is a code I have to enter into it. Does anyone know how or where I can get a code? I probably have to go to the dealer, but he is in Bullhead and I'm in Corona.