My car originally had XM and still has OnStar. But now I switched to Sirius. Is there any way to make the wing antenna on the back work for Sirius? Or can I remove it and get something smaller for just the OnStar? I first had the Sirius antenna on the roof next to the passanger door, but got sick of looking at it and am trying it on the inside of the windshield. Seems to be working great there so far. I have already removed the center 'RC' antenna and replaced it with an electronic windshield antenna that works well. NOW, if I could just get rid of the back antenna, then I could get the roof looking smooth and clean

 

Since you have Onstar I think you are stuck with the "wing".

I have heard of people being able to use the XM antenna for Sirius.

Of course you could've waited to see if the XM/Sirius merger goes through, then you would've had some degree of Sirius on your factory XM

 

I thought someone did a how-to on this actually, I have been known to be wrong though.

 

Try here:
https://www.chevyhhr.net/forums/show...sirius+antenna