Help me understand my alarm
 

I bought my 2002 bug eye impreza wrx with an alarm already fitted so I don't know much about it, apart from how it works.

The problem is that it doesn't make a sound.

If I sit in the car and move about to trigger the interior sensors the indicators flash for about 20 seconds but no sound.
If I open any of the doors without disabling the alarm the indicators flash but no sound.
If I disable the alarm and not open any doors the alarm re-activates itself after a few minutes.
The key fob is black with a blue subaru sticker, it has one button.
The car is fitted with a tracker monitor.
I can rock the car and kick its wheel but nothing happens.

Is it faulty?

Sounds like the siren is faulty.

Kicking the car and rocking it will make no difference as it doesn't have sensors which can pick this up.

No doubt Sigma Sam will correct me :(

The vehicle will be fitted with a Sigma M30 system.
Do you know if the vehicles battery has been flat recently? (Been in a bodyshop perhaps?)
If the vehicles battery runs flat, it has been known for the alarm unit and siren to fall out of sync. This is due to the fact that the self powered siren on the M30 also contains a processor chip that is continually in communication with the alarm unit. When the vehicle battery runs flat this communication stops, and as the siren is self powered continues to look for the data from the alarm. Usually charging the vehicle's battery is sufficient and the two units communicate again without any problem, however it has been know for the same situation you describe to occur.

To remedy this, with the system disarmed, you will need to disconnect the 4-pole siren plug at the alarm unit. Identify pins 1 and 3 (identified in the connector moulding) in the siren lead's 4-pole connector and short these wires across briefly with a length of wire - 10 seconds should be more than sufficient. This has the effect of re-setting the siren's processor and should enable normal operation from the siren when re-connected.
If this doesn't work then it could be a fault within the siren itself, but these are rare and I would go down the above route first, before looking to purchase another.

With regard your method of testing the ultrasonics, the Sigma system will detect your presence in the vehicle during the threshold time and automatically reduce the ultrasonic sensitivity to prevent a false trigger. Possibly to the point where your movement in the car when the system becomes fully armed is ignored - if sufficient movement was detected during the Threshold time.
If you can PM me your e-mail address I can send you a PDF version of the operating instruction to explain all the functions of your alarm and detail more fully how the ultrasonic sensors work and the most effective way to test them.

With regard kicking and rocking the car to generate a trigger, there are no tilt or shock sensors included with the standard fit system (although a tilt sensor is currently undergoig Thatcham testing which will be introduced on the forthcoming Subaru Tribeca later this year).
However, when the ultrasonic sensors are set up correctly, I would expect a larger impact (such as the vehicle being struck by another) to generate enough air movement within the cabin to trigger the ultrasonics.

SS

I cant find where the alarm is installed.

You should have e-mail

SS