See also:

Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance. However, if a customer wishes to write or e-mail GMC, the letter should be addressed to: United States GMC Customer Assistance ...

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

Engine Cooling When Trailer Towing
The cooling system may temporarily overheat during severe operating conditions. See Engine Overheating on page 10‑20. ...