Ok I know this sounds stupid but today I tried wiring a horn up to my friend’s trailblazer and I just can’t seem to get it to work and I have no clue why because I have wired a few horns and have not had a problem and there are no instructions. 1st off the horn has 2 prongs coming from it. 2nd off the button has 2 wires coming from it one black white and a green wire. Also I have a hot wire that I put on that is red. So can anyone help me out I would like to fix it tonight if possible. Thanks

 

Also right at the button the green wire comes out and has a round conector so I grounded it to the bolt that clamps the button to the handelbars.

 

Anyone?? this is driving me crazy.

 

Usually, there is a relay in the horn circuit because they can pull some current., and you dont want that much current going thru the button.
Dc is pretty simple, just power in and ground.
One wire of the button, goes to the 12 volt plus, the other goes to the relay. The other side of that circuit goes to ground. When the button is pushed, the electro magnet in the relay closes...and allows power to flow in the horn circuit. One power lead goes in the relay, and the the other wire comes out to the horn. The second wire from the horn goes to ground.
If you go to radio shack and buy the relay, the sales clerk will draw you a simple diagram on how to wire it. Oh ya...as long as your buying the relay, get an in line fuse, and wire it into the horn circuit, they have those at radio shack too.