Testing the Alarm
To test the alarm:
1. From inside the vehicle, lower the driver side window, and open the driver door.
2. Press 
.
3. Get out of the vehicle, close the door, and wait for the security light to go out.
4. Reach in through the window, unlock the door with the manual door lock, and open the door.
This should set off the alarm.
If the alarm does not sound when it should, but the headlamps flash, check to see if the horn works.
The horn fuse may be blown.
To replace the fuse, see Fuses and Circuit Breakers on page 10‑31.
If the alarm does not sound or the headlamps do not flash, see your dealer for service.
See also:
Engine Compartment Fuse Block
If the vehicle has a diesel engine, see the Duramax Diesel supplement for more information.
If the vehicle is a hybrid, see the hybrid supplement for more information.
The Engine Compartment Fuse Bl ...
License Plate Lamp
To replace one of these bulbs:
1. Open the liftgate partway. See Liftgate on page 2‑9.
Passenger Side Shown, Driver Side Similar
2. Push the left end of the lamp assembly toward the right.
...
Unable to Connect to OnStar Message
If there is limited cellular coverage or the cellular network has reached maximum capacity, this message may come on. Push to try the call again or try again after driving a few miles into another ce ...