Take out the 2 7mm screws on the panel where your knees are when youre driving. After that there should be a metal plate held on by 4 bolts. Take those off and remove the plate. You should see a bunch of wires coming down from the steering column. Thats where 90% of the alarms out there get there power. See if you have any wires coming off that that dont appear to be stock. Definetely sounds like theres an alarm on it and they just cut the wire for the siren.