Alarm fault

[Passat_ben]

Hi guys, I've another fault to fix.

After locking my car but not realising I had left a window open I came back to it on the drive and the alarm triggered in that the lights all flash however I have no siren.

I played about abit and when leaning into the car it doesn't seem to trigger however it would when using the internal door handle.

This was discovered by trying to simulate someone trying to get into the car.

Can someone tell me where the siren should be so I can check. Also should the internal sensors work? Where are they?