I had a quick demo at the dealer and then when I got home it wouldn't work. I pulled out the ivr, checked wiring a number of times and couldn't figure it out. Finally I got it working, but I don't have it around to verify the settings. I want to say the TV setting for audio out needs to be set to fixed (not variable) and perhaps this can't be changed (or seen) unless you have the TV speakers set to off. Then the aux works on the IVR for audio output.
I spent a few hours pulling out the ivr, checking cables, got some spare speakers to test with, etc and it was just this setting on the TV. I probably changed it running the TV setup when I got home without knowing it broke the audio output.