The multi-band antenna is located on the roof of the vehicle. The antenna is used for the AM/FM radio, OnStar® and the XM™ Satellite Radio Service System, if the vehicle has these features. Keep the antenna clear of obstructions for clear reception. If the vehicle has a sunroof, the performance of the AM/FM radio, OnStar®, and the XM system may be affected if the sunroof is open.