Im pretty sure the stock alarms are placed near th efuse box by he drivers side if not, you may have to get under your dash and reach up by the firewall for the brain.

my friends alarm would go off for any number of reasons so we unplugged the alarm brain and the car works fine.

Most alarms have a fail safe if the brain fails you can just disconnect it and continue using your car without an alarm.

if you find it and disconnect it and your car doesnt start then plug it back in and we'll keep thinking whatelse it can be.