2005 Chevy Venture....Circuit City tried to install three SIR-GM1's. One was mine (Crutchfield) and two were off their shelves. Two of the Sirius units were never recognized by the GM head unit. One actually briefly showed "UPDATING" on channel 184 when we unplugged and replugged the radio itself..then it did nothing. At no time did the other two ever display SR1 or SR2..or even show any sign of the head unit detecting the GM1.... The HU has the BAND/CD-AUX button so it SHOULD work as a plug n play unit..and one of the units DID briefly seem to show some satellite life. The Venture did NOT have XM installed at the factory..so maybe the AUX input needs to be activated by the dealer? I dunno..anyone have experience or suggestions? Thanks David.