See also:

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 acce ...

Add-on Electrical Equipment
The OnStar system is integrated into the electrical architecture of the vehicle. Do not add any electrical equipment. See Add-On Electrical Equipment. Added electrical equipment may interfer ...

Engine Coolant Temperature Warning Light
This light comes on briefly while starting the vehicle. If it does not, have the vehicle serviced by the dealer/retailer. If the system is working normally the indicator light goes off. Noti ...