Alarm works but doesnt make any sound?

[NPCTNUSA]

Hey I got some questions and going to post them all up seperate cause i got a couple different problems so first problem. I got a 95 talon tsi awd and my alarm works the lights blink and the key fob works, i got a little black thing with the green and red lights by the shifter and it works great, but when the alarm goes off it doesnt make any sound like it did when my cousin had it, he had something done to it and it stopped after that. Just wondering if anybody could tell me what possibly is going on here

 

[Chuckster]

The siren typically grounds with the mounting bracket. Loosen and tighten the bracket-to-car screws or bolts and see if that fixes it. Clean a decent electrical path if it works after that.

If not, get the test light out and start chasing the wires.