[ShagginJet]

you can just look at the alarm unit you have, get online and find the wiring diagram. then it'll tell you what line is used for the horn. Take that wire and cut it about 1 foot off of the brain, cap the wire that goes to the horn, then use the brain side to run a wire up to your ignition consol. Use a multi meter to figure out what wire is the lights, then use a 12v source to double check that. double check that the horn out is 12v too. if all is good, splice the wire at the ignition and you're done... BAM!!

I've done this before, it's really easy, takes about 30 mins and just some electrical know how.