See also:

Auxiliary Roof-Mounted Lamp
If the vehicle has this feature, this button includes wiring provisions for a dealer or a qualified service center to install an auxiliary roof lamp. This button is located on the overhead console. ...

When the System Does Not Seem to Work Properly
The following messages may be displayed on the DIC: SERVICE PARK ASSIST: If this message occurs, take the vehicle to your dealer to repair the system. PARK ASST BLOCKED SEE OWNERS MANUAL: This messa ...

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 ...