You're going to reroute the existing wires from the stock horn. These will trigger the Stebel. You will need a fused line from the battery. The Stebel draws a lot of current. You will have a solenoid that can be mounted easily under the left side panel. Some, myself included, have mounted the horn under the left side panel as well by bolting it to the side of the air box. So easy, a caveman can do it Do a search for Stebel, Nautilus, Air horn etc etc
I heard you are the expert on wiring the Stebel air horns. I got my installed today, mounted to the air box under the left side cover. I discovered the the stock Rocket horn uses a ground horn button, where the hot wire to the horn is always hot and the button completes the ground circuit. This threw the screws to me when I tried to figure out the relay. I found the attached photo on a web site. It this the way you wired yours, and does this work with a negative horn button?