GMC 2006 Sierra - Manual (Page 114)

The horn may chirp for 10 seconds before the alarm
goes off if the theft-deterrent system is activated using
the remote keyless entry transmitter and the driver’s door
is opened. If this occurs, you can turn off the alarm by
pressing unlock on the remote keyless entry transmitter
or by placing the key in the ignition and turning it to
START.
Here is how 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 remote keyless entry
transmitter.
If you set off the alarm by accident, turn off the alarm by
pressing unlock on the remote keyless entry transmitter
or by placing the key in the ignition and turning it to
START.
Testing the Alarm
The alarm can be tested by following these steps:
1. From inside the vehicle, activate the system by
locking the doors with the remote keyless entry
transmitter.
2. Wait for the security light to go out.
3. Unlock the door with the manual door lock and
open the door. This should set off the alarm.
4. Turn off the alarm by pressing unlock on the remote
keyless entry transmitter or by placing the key in
the ignition and turning it to START.
If the alarm does not sound when it should, but the
vehicle’s headlamps flash, check to see if the horn
works. The horn fuse may be blown. To replace the
fuse, see Instrument Panel Fuse Block on page 5-124
and Underhood Fuse Block on page 5-127.
If the alarm does not sound or the vehicle’s headlamps
do not flash, see your dealer for service.
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