See also:

Twilight Sentinel
This feature automatically turns the lamps on and off. A light sensor on top of the instrument panel makes the Twilight Sentinel® work, so be sure it is not covered. With Twilight Sentinel th ...

Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems. It also checks the tire pressures, if the v ...

Customer Assistance Offices (Mexico)
To contact the Customer Assistance Center (CAC), use the phone numbers listed in this section. Customer assistance is available Monday through Friday, 08:00 to 20:00 hours, and Saturdays from 08: ...