shock sensor adjustment

My theory on shock sensors is that if you have to set them high on sensitivty, they are not properly located to pick up vibrations from any impact to your vehicle. I have two 504Ds installed in my car..one behind the front dash velcroed to a air duct which picks up front impacts, and another towards the rear of the vehicle in a backseat center console, velcroed to a plastic panel inside of that piece. My sensitivity is set at mid level.  You can also try mounting to wire harnesses..zip tie them works good. Generally lightly banging on the bumpers or doors, frame.. triggers the warn away.. and of course a harder hit triggers full alarm.