TTY Users
OnStar has the ability to communicate to the deaf, hard-of-hearing, or speech-impaired customers while in the vehicle. The available dealer-installed TTY system can provide in-vehicle access to all of the OnStar services, except Virtual Advisor and OnStar Turn-by-Turn Navigation.
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 ...
Courtesy Lamps
The courtesy lamps automatically come on when a door is opened.
The lamps can also be turned on manually by fully turning the instrument panel brightness control clockwise.
The reading lamps, locate ...
How the System Works
The LDW camera sensor is on the windshield ahead of the rearview mirror.
To turn LDW on and off, press the LANE DEPART control on the steering wheel.
The control indicator will light when LDW is ...