why may radio connect to xm satellite radio?

Hello, the antenna has been replaced, but have you checked and ensured antenna cable integrity? There is a test procedure to follow on this using a GDS diagnostic tool, but it seems like your dealership would have done this. I'm pretty certain that the dealership isn't scratching their heads -- if they are, find a new dealership! With the amount of technical resources and training afforded to dealership technicians, they can resolve anything if they are skilled.