haha, im sooo doing that to my friend once i get home. im guessing all that you would do is run some wire spliced to the break light wire all the way to the horn so when the lights light up, it'll send electricity to the horn and it'll go off. does that sound about right...???
haha, i kinda did that to my friends 1986 beamer, u know to teach him not to leave his keys in the ignition... but he didn't have a fuse that goes just to his brakes so i ended up wiring it into the headlights... whats even funnier was that he was talking to me on the phone when he turned his lights on... he was like "what the f**k is that sound?" it was all i could do to keep from cracking up.
LOL, I would do that to my kids when it's time to teach them how to drive, or when they try to sneak out of the house and take the car when they are in trouble.