The trunk is wired to the trunk release, which is wired in glove box. All other wires are are under dash. There is a mercury switch that when it's set, shows any movment to car, window breaking, doors or trunk opening, ect.
The one I have on Chevy also will go off if you put your hand in the the window while it's opened.
They can be set up to have horn go off when set. But we have enough noise out there.
