most cars use 2 wire horns, use grounding to make the horn blow. thats why you often hear horns blowing after accidents by grounding switching you can several things setup to blow the horn with out having a mess of relays or getting feedback to things you don't want to energize like air bags.
XD9 service, Dark Earth
"This year will go down in history. For the first time, a civilized nation has full gun registration. Our streets will be safer, our police more efficient, and the world will follow our lead into the future!" -Adolf Hitler,1935" Th