I just purchased an 04 SS and it has what looks like the old style Cell phone antenna mounted to the glass on the upper left rear window. I'm thinking this can't be for a cell phone and I've seen it on a few Chevrolets. Anybody know what it's for?

 

It is for the vehicles OnStar service, mine fell off.

The black triangle hockey puck on theroof is for XM stereo.

 

Thats what I thought. Thanks. I didn't think that in 2004, people still hard wired their cell phones in the car.

 

Mine fell off, also, and I put it back on with some 3M tape. I was quoted $300 to have the Chevy dealer do it. Cost me squat! I was considering replacing my XM antenna with the '05 antenna which has both Onstar and XM, but the wiring got involved. The XM wiring is on the right side, but Onstar is on the left. Also, my Onstar box is no longer in the back left side of the trunk, but it's tucked up under the window tray now.

 

Now your car is just a bit more aerodynamic.