I just installed an AVIC-7200NEX in my 2007 Yukon with bose system.  I used the Maestro RR with GM05+ wiring harness.  

Everything works, EXCEPT no audio to speakers.  No buzzing, crackling, nothing.  GPS, good.  Steering Wheel Contols, Great!  But no audio from any source, other than the little chime speaker.  Any ideas?