Again I tried all the controls, check the cassette, then checked the intercom cables. Lo and behold, I looked at the front rider's cable end with cover held in place by the clip. Popping off the rubber dust cover, found it full of water. Turned it upside down, and a thimble full flowed out. After shaking all the water out, radio volume returned. Water somehow got in the last time I washed the bike.
You think you've see everything, and then something hits you unexpectedly.

I'm glad I don't have to mess with any of the electronics, false positive fixed.
