See also:

Hazard Warning Flashers
(Hazard Warning Flasher): Press this button, on the center of the instrument panel, to make the front and rear turn signal lamps flash on and off. This warns others that you are having trouble. ...

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 ...

XM™ Satellite Radio Service
XM Satellite Radio Service gives digital radio reception from coast to coast in the 48 contiguous United States, and in Canada. Just as with FM, tall buildings or hills can interfere with satellite ra ...