TX-NR616 with ARC problems

Completed the install for a new system today. All new components consisting of LG Model 55LM7600, Onkyo TX-NR616, LG Model BP520 and cable box as TV source. Smart TV needs the ARC to function for all the Smart features such as Netflick, VUDU, etc. Set everything up and could not get ARC to function. Spent my 1 hour with Tech support who walked me through all programming without changing any settings. RIHD is enabled and ARC in 'Auto'. TV/CD output is selected and ARC is selected in settings. The LG TV actually has an ARC setting and that also enables ARC. The ARC indicator on the front panel 'never' turns on. Tech support finally said, I don't know how to help you any further. Since the ARC indicator never comes on, your TV must not be outputting a signal.
I'm not sure how he can say that but how can I confirm the receiver ARC function is active and not receiving a signal?
Also, has anyone else had problems with ARC. I can't afford to plan 30 minutes in a customers' house for simple system demo and spend 4 hours struggling with ARC.