Zippy, Frank, guys,
I have exactly the same problem with my 06 Street Glide!!!
I posted in the following thread: "NO SOUND on the stereo Harman Kardon (STREET GLIDE 06)"
Some guy has just posted there that a open speaker code refers to a speaker broken and muste be replaced.
I also checked the common suspects you talked about Zippy and everything seems to be fine.
INCREDIBLE!!: also find out that the fairing botton left screw, was not there!!!
DOUBT: Your problem was repaired in deed after the open internal circuit diagnosticaded by the stealer????
I got my stereo from the dealer. It was a broken circuit within the stereo. Aparently is a very tiny failure. They did'nt charged me anything (warranty expired 3 months ago).
Great service at Satelite HD!!!!! (here in Mexico City)