External wired siren doesn't work

Hello bro.

First you have to check if your siren is working normally without the host. You can test it verifing the Continuity of the wires with a multimeter or, connecting the siren Jack at a 9 volts battery and check if it sounds (ask help for a Electronic technician). If doesn't sounds it means that the siren is Broke and you have to buy a new one (not that expensive, here at Brazil we found it for about 4 dollars).