I have a quick question and can't seem to find this information anywhere. I have had a ton of trouble with my dealer not knowing a lot about the 07's. They first told me that there was no factory starter kit available, then they told me that the 07's still had separate antennas for the XM and onstar. Well, after reading posts on here and looking at other Avalanche's on the lot I am pretty certain that the one antenna performs both functions.

So I have the 6 disc CD changer and Onstar in my avalanche. I don't have the XM option. I have found the onstar antennas right underneath the HVAC controls. There seems to be two antennas for the onstar setup. Not sure why? Does anyone know where the XM antenna terminates? I am looking to hook up a Sirius Sat. receiver up to the existing XM antenna and would love to know where I can find the coax. If I didn't get the XM option does that mean they didn't run a third coax from the antenna? Can I just pull off the trim and run an extension cable to the antenna?

Any help would be greatly appreciated. Thanks!!

u might want to try and post this on the tahoe forum since these vehicles are almost identical...

XM Tuners are availablefrom GMfor 07 models
took me 30 min. to installit, including new antenna that comes with kit