See also:

End a Call
Push . System responds: “Call ended.” ...

Manual Rearview Mirror
Hold the mirror in the center to move it for a clearer view of behind your vehicle. Adjust the mirror to avoid glare from the headlamps behind you. Push the tab at the bottom of the mirror forward for ...

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 ...