i have a sigma s30 alarm and i would like to fit a small siren inside the car so if someone gets in hopefully the sound will be too bad to hang around i mean one of those very small ear shattering sirens.what i would like to know if i broke into the wiring from control modual which goes to external siren and connected small siren to live and earth would this be ok. thanks for any help

 

Firstly, are you sure that the system is an S30? The standard fit Subaru system is the M30.
Secondly, the output from the ECU to the battery back-up siren is a coded digital signal, so the existing cable cannot be spliced into.
There is however, a low current negative output from both the above units that could be used as you require. However, depending on the current draw of the siren that you intend to use, you may require a relay to prevent damage to the output that is rated at 300mA max.
If the system is indeed the standard fit Subaru system, then this output is not usually used and so the wire is missing from the alarm connector.
If all this hasn't already put you off, PM me confirming the system type, whether the system is a UK Subaru fitted system or not and I can identify the terminal that you require on the connector and any programming info that may be required.
SS