- 1). Inspect the horn's fuse inside the fuse box (usually under the hood) and the wiring. Replace the fuse if it is burned out and reconnect any wires that have been disconnected from the wiring harness. If you find and correct any of these problems, test the horn again to see if it now works.
- 2). Adjust the adjustment screw on the horn's body. The screw can require either a flathead or Phillips screwdriver, depending on the car model and type of horn. Turn the screw tighter and listen for the horn to sound more and more. When it changes to a raspy sound, turn the screw in the opposite direction until you get the right sound.
- 3). Remove the old horn from the vehicle by disconnecting its electrical connector and unscrewing the horn from its mounting bracket. Compare your replacement horn to the old horn and see if it will securely fit in the old bracket; this isn't a problem if you're replacing it with a stock horn. Use another bracket designed for your new horn if you're not completely sure about the old bracket.
- 4). Install the new horn in the car. If you're using a brand new horn and bracket, you may need to install the horn in a new location. Standard locations for installing the horn are under the battery, behind the grille or between the fender and inner fender. Check your new horn's installation instructions for a recommended location.
- 5). Connect the wiring to the replacement horn. If the horn won't work with the original wiring harness, you will need to connect the wires for both the car and the horn together. Soldering is the best method. Place the solder on the bare wire leads as you apply the heat gun to it, then insulate the leads with heat-shrink wrapping.