Look up under the dash driver's side and look for a wire connector with probably 10 or so wires in a straight connector. If it is aftermarket it will be hanging loose or tie wrapped up and disconnect it. That usually kills them. If it is factory, probably a module under there, and most are labeled "security system" or something similar. I've never looked for a factory one on a ford, so this is generic of course- but most are under the dash and a simple unplug will do it. GM's are a whole different animal. Edit: Reread ur post, its a factory unit. It may be able to be disconnected easily by unplugging but not sure. Guess I wasn't much help heehee. But no, it won't damage anything to try- disconnect and see if it starts. If it doesn't plug it back up and google it if you don't get better responses than mine on here.