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 ...

Turning the Rear Vision Camera System Off or On
To turn off the rear vision camera system, press and hold , located on the inside rearview mirror, until the left indicator light turns off. The rear vision camera display is now disabled. To turn t ...

Instrument Panel Illumination Control
(Instrument Panel Brightness): This feature controls the brightness of the instrument panel lights and is located next to the exterior lamps control. Push the knob to extend out and then it can be ...