A8L01Miami

A few years back I replaced the Symphony head unit with RNS-D (CD based), added the TMC and a Neo-Ipod unit for ipod integration. All worked flawlessly until last week, when the communication between the radio/nav head unit and the dash stopped. All other systems appear to be working fine, meaning that all other messages are showing fine. Only the Radio/Nav messages are gone. I took the original Symphony head unit and put it back in the car, and the messages from the radio do not show either. It pretty much narrows it to the dash area. Any ideas?