like stated above, its passive, it will not allow you to start the car without the proper coded key. Each key has a little chip in it, that sends a code to the computer and if that code is correct then the car will start, if the code is not right, or you try to hotwire the car, it will not start.
the fords that ive owned that had an alarm never would go off if it was hit or touched or the door was opened with out the remote...
i think it is an after amrket alarm, if it is, than you need to look around and try to find a computer box for it, and follow the wires to the sensor and it will have a manual adjustment and use a screw diriver or what ever will work to turn the analog adjuster. and of course lefty loosey, aan righty tighty, so loose is less sensative.
the problem that i had with mine was, it had a montion detector that was touchy as hell, i just cut the wire and used the vibration sensor and turned it down like how i explianed.
hope this helps. my local car stero shop told me over the phone how to do it. you may want to call yours and see if they can help you. couldnt hurt?!?