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 ...

Using the “Digit Store” Command
If an unwanted number is recognized by the system, say “Clear” at any time to clear the last number. To hear all of the numbers recognized by the system, say “Verify” at any time. 1. Press a ...

Reporting Safety Defects to the United States Government
If you believe that your vehicle has a defect which could cause a crash or could cause injury or death, you should immediately inform the National Highway Traffic Safety Administration (NHTSA) in addi ...