See also:

Underbody Maintenance
Use plain water to flush dirt and debris from the vehicle's underbody. Your dealer or an underbody car washing system can do this. If not removed, rust and corrosion can develop. ...

Entering the Feature Settings Menu
1. Turn the ignition on and place the vehicle in P (Park). To avoid excessive drain on the battery, turn the headlamps off. 2. Press the customization button to scroll through the available customiz ...

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 ...