GMC Sierra Owners Manual
Anti-theft Alarm System
This vehicle may have a content theft-deterrent alarm system.
This is the security light.
To arm the theft-deterrent system:
1. Open the door.
2. Lock the door with the Remote Keyless Entry (RKE) transmitter.
The security light should flash.
If the delayed locking feature is active, the alarm will not be activated until all doors are closed and the security light goes off.
3. Close all doors. The security light will stop flashing and go off after approximately 30 seconds.
The system is armed when the security light goes off.
If a locked driver door is opened without using the RKE transmitter, a 10 second pre-alarm will occur. The horn will chirp and the lights will flash. If the key is not placed in the ignition and turned to START or the door is not unlocked by pressing the unlock button on the RKE transmitter during the 10 second pre-alarm, the alarm will go off. The vehicle's headlamps will flash and the horn will sound for about 30 seconds, then will turn off to save the battery power.
The theft-deterrent system will not activate if the doors are locked with the key or the manual door lock.
It activates only if you use the power door lock switch or the RKE transmitter. The vehicle can be started with the correct key if the alarm is set off.
To avoid setting off the alarm by accident:
• If you do not want to activate the theft-deterrent system, the vehicle should be locked with the door key after the doors are closed.
• Always unlock a door with the RKE transmitter.
If the alarm is set off, press unlock on the RKE transmitter or place the key in the ignition and turn it to START.
Testing the Alarm
To test the alarm:
1. Lower the driver window and open the driver door.
2. Press lock on the RKE transmitter.
3. 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 10‑47.
If the alarm does not sound or the headlamps do not flash, see your dealer for service.