2006 Tahoe Radio Will Not Tune?

[cljtamu]

This is a STRANGE issue! We just purchased a 2006 Tahoe and the FM/AM Radio will not tune. Say I am trying to tune to 98.9 - I can hear the station on 98.7 (static, poor reception, but there) but as soon as you tune it to the actual station, 98.9 there is nothing. No static, no sound, nothing. The CD and Rear Audio System work fine. I'm not sure about the XM because I haven't subscribed yet. I pulled the head unit to make sure the antenna was still connected and it seems to be. I haven't seen any other posts regarding a similar issue and would really like to avoid taking it to the dealership. Would appreciate any thoughts!