2017+ Ford F250/350
You've got your horn kit assembled and you're almost ready to make some noise. If you're having trouble finding the OEM wire to tap into, this article serves to help you out. Check out the schematic below. If you're not familiar with these, don't worry, we've got you covered.
Getting Started
This guide will require you to splice or tap into a specific wire for the horn. Looking at the diagram above, the horn wire for your vehicle is brown. Locate the OEM horn under the hood and look for a two-wire connector going into the horn. The wires may be wrapped an an electrical tape of some sort. Peel the tape back to reveal the two leads. Look for the yellow wire.
Use the included T-tap connector to splice a new 18-gauge lead off the yellow horn wire. The negative lead is black. Do not splice into the black wire. If you're not sure about how to do this, please see the following video.
Once you've got your new lead tapped off the OEM horn, route it back our train horn valve. You can use a toggle switch between the valve and OEM horn to turn the train horn on and off at the wheel. With the switch off, the wheel just honks the OEM horn. When you flip the switch on, the wheel honks the train horn along with the stock horn.