See also:

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 ...

Service Vehicle Messages
SERVICE A/C (Air Conditioning) SYSTEM This message displays when the electronic sensors that control the air conditioning and heating systems are no longer working. Have the climate control system s ...

Add-On Electrical Equipment
Notice: Do not add anything electrical to the vehicle unless you check with your dealer first. Some electrical equipment can damage the vehicle and the damage would not be covered by the vehicle's wa ...