Vehicle and Power Issues
OnStar services require a vehicle electrical system, wireless service, and GPS satellite technologies to be available and operating for features to function properly. These systems may not operate if the battery is discharged or disconnected.
See also:
Warning Lights, Gauges, and Indicators
Warning lights and gauges can signal that something is wrong before it becomes
serious enough to cause an expensive repair or replacement. Paying attention to
the warning lights and gauges could p ...
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 ...
Checking Coolant
The vehicle must be on a level surface when checking the coolant level.
Check to see if coolant is visible in the coolant recovery tank. If the coolant inside the coolant recovery tank is boiling, do ...