How do I wire my train horns to the alarm?

Not sure how to wire the horn to go off when the door is opened. Well, I could describe how to do that, but I don't know how to control it with the remote.

One thing I have always wanted to do is wire up a starter kill in such a way that when someone tries to start the truck, it instead locks the horn on. Very effective if using air horns and it's parked in your driveway at 3AM with you inside. Trouble is, at that point they have already broken the ignition lock and caused damage.

 

The neighborhood will love you when a cat jumps on it at 3 am and sets it off.

False alarms suck but do happen.