See also:

Other Navigation Services Available from OnStar
OnStar eNav: Allows subscribers to send destinations from Google Maps™ and MapQuest.com to their Turn-by-Turn Navigation or screen-based navigation system. When ready, the directions will be downlo ...

Passing
More passing distance is needed when towing a trailer. The combination will not accelerate as quickly and is longer so it is necessary to go much farther beyond the passed vehicle before returning to ...

Customer Assistance for Text Telephone (TTY) Users (U.S. and Canada)
To assist customers who are deaf, hard of hearing, or speech impaired and who use Text Telephones (TTYs), GMC has TTY equipment available at its Customer Assistance Center. Any TTY user can communicat ...