See also:

Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance. However, if a customer wishes to write or e-mail GMC, the letter should be addressed to: United States GMC Customer Assistance ...

Transmission
Electronic Range Select (ERS) Mode ERS mode allows you to choose the top-gear limit of the transmission and the vehicle's speed while driving downhill or towing a trailer. The vehicle has an electro ...

Multi-Band Antenna
The multi-band antenna is on the roof of the vehicle. The antenna is used for the AM&-FM radio, OnStar, the XM Satellite Radio Service System, and GPS (Global Positioning System), if the vehic ...