alarm Siran

[only one vinnie]

Any one help again please. Im trying to iron out a couple off issue's i have with me A4 Convert 2003, One is the alarm it's all set fine and triggers off fine ie hazard flash but no siren'
can the siren be turned off on it's own maybe from the last owner ??

 

[AlexGSi2000]

The siren will be dead.
Over time, the backup batteries in the siren leak - this damages the siren circuitry.

Only solution is to replace the siren - 2nd hand ones can be had for around £20 from ebay.