Ok, does anyone know if the XM antenna is installed even if you dont have XM radio?

If not, I read somewhere that it would be easy to put the after market XM antenna under the black plastic cover that is on the back of the car?

Part II
Is it possible to place the GPS antenna under the regular antenna in the front of the vehichile under the AM/FM mast antenna box?

 

I have an 08. The XM antenna is installed on my 08 in the base of the OnStar short antenna located on the rear roof. My vehicle did not come with XM, but I still have the antenna.

 

Sparky
Is the antenna actually under the plastic cover? I found an article how to use the XM antenna on a Pioneer AVIC d3.

Tanks
JV

 

I've never taken the base off. I saw a 06 or 07 with XM and it had just the black base on the rear roof without hole for OnStar antenna. In 08's I think all HHR's come with OnStar so they used the XM base as part of the OnStar antenna.