See also:

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 ...

Instrument Panel Illumination Control
This control is located on the instrument panel, to the left of the steering column. (Instrument Panel Brightness): Turn clockwise or counterclockwise to brighten or dim the lights. ...

Compass Zone
The zone is set to zone eight upon leaving the factory. Your dealer will set the correct zone for your location. Under certain circumstances, such as during a long distance cross-country trip or movi ...