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:
Charging System Light
The charging system light comes on briefly when the ignition is turned on, but
the engine is not running, as a check to show the light is working. The light turns
off when the engine is started. ...
Tire Pressure
If the vehicle has the Tire Pressure Monitor System (TPMS), the pressure for each tire can be viewed in the DIC. The tire pressure will be shown in either kilopascals (kPa) or pounds per square inch ( ...
Rear Window Defogger
REAR (Rear Defogger): Press to turn
the rear window defogger on or off. The rear window defogger turns off after about
10 minutes. It can also be turned off by turning the ignition to ACC/ACCESSO ...