I have a 2002 LeSabre with an XM Roady 2 installed. When I bought my 05 truck I made sure that the XM radio was included. Driving the new truck to work the radio cut out while going under an underpass of a 6 lane freeway, I never noticed this with the Roady. So while driving to work today with the Roady I set the display to antenna aiming and while driving under the underpass the satellite signal went to 0 bars, but the terrestrial signal was at 3 bars; the music never stopped.

Is there a way to see if the GM built-in XM is receiving the terrestrial signal as well as the satellite signal? Thanks for your responses- the dealer just looked puzzled when I asked.

Dan