You could also design a circuit that has a 555 timer and some resistors and hook it up to a 12 volt battery the 555 timer is programed to go off and back on every second
im sure he is not trying to wire a bread board. he know nothing about designin a circuit. but yea, something like that could work. with a timer and some ands and ors gates.
they sell alarm lights at my local shop that can be used without an alarm to fool people. You just find a 12v wire and splice into it. The LED just blinks on and off. However, there are some alarm lights out there that you can tell if they are real or fake by looking at them. I'm don't remember the way they blink, but alarm lights are supposed to blink a certain way. If they blink a different way, then it's fake.
or you can get an actual alarm. they do sell some real cheap ones. if you wanted a fake one originally then you wouldn't mind the quality of the alarm.
Like Young James said, there are some at my local car audio shop. Maybe you can find some on google in the car electronics section if you aren't going to get a real alarm.
