Xm Antenna Help

SiriusFan · October 7, 2007

My 2008 Sierra is in, although I havn't picked it up yet since I am busy the dealer sent me pictures. I ordered it without XM but the pictures show the XM antenna installed. I did not order onstar either so I am wondering did they install the antenna anyway. Either way where would the XM brains sit so that if the wire is run I can use the antenna for my sirius install. Also if the antenna is just there an not wire is run what is the easist way to pop the headliner out (with sun roof) so that I can run a wire to where my sirius is going to sit.

I am also under the impression that this antenna is not the same as the terristrial antenna since that is embedded in the glass.

Thank You,

dsmazz · October 7, 2007

Onstar is standard, unless you ordered a work truck. If you have XM (I read on some post somewhere that XM might be standard on '08s), the same antenna is used for both. If you don't have XM, the Onstar antenna has to be changed out for the dual-purpose antenna. The dual purpose antenna was at one time, only available by purchasing the GM XM kit. It may now be available separately; you'd have to check with your dealer.

From outward appearance, either the Onstar-only or the dual purpose antenna look the same. However, internally, they are different. You can't simply add a wire to the Onstar-only antenna to work with satellite radio. Also, if you don't have XM, there won't be a lead and there won't be the XM receiver. If you do have XM, the receiver is located on the forward side of a metal brace bar behind the glove box. There are two screws that secure the bracket to the brace. One screw is not too hard to reach, the other is rather difficult.

Removal of the headliner is not required, but you would have to remove the overhead console, both sun visors, and both a-pillar mouldings, in order to "lower" the front of the headlinder and then hope your hands are small enough to fit up between the headlinder and the roof to make the necessary connections.

05Quadrasteer · October 8, 2007

One other reason you might be seeing what you think is the XM antenna on top is that GM has integrated the regular radio into the same antenna. Now all three signals; XM, On-star, AM-FM come threw the one antenna on top.

Have a nice day.

Bill

SiriusFan · October 16, 2007

I finally picked up my truck today and what a shock it was to find out that XM was in fact installed in the truck. However my trailer package was not so that is something I need to hunt down.