Automobile horns provide a very important function while either driving the vehicle or while parked. They serve as immediate warning devices to attract other drivers, cyclists or pedestrians of impending danger, or as a means to warn others of a hazardous situation. Sometimes we also need to warn animals of our approach. Occasionally our horns malfunction through the steering wheel contact switch, or we simply want a backup system. Universal horn buttons can provide that extra assurance. They can be installed by any vehicle owner, using a few steps and simple tools.
Purchase your universal horn button kit. Note whether you want a double wire horn button or a single wire button. The single wire button will require only one wire connection, which will be a hot (positive) wire to the fuse block or to original horn wire in the horn wiring loom. The single wire button requires that you mount the button directly into the metal of the dashboard frame or some other metal source. The double wire button will require grounding the extra wire to the chassis or some part of the metal frame.
Place the vehicle in park or neutral with the emergency brake set. Disconnect the negative battery cable with a socket and wrench. Raise the hood and locate the original equipment horn. There will be only one wire attached to a tang protruding from the horn, which will be the hot wire. Follow this wire back toward the dashboard as far as you can. You might have to slit the loom to locate it. Find a good spot to cut the wire with wire strippers. Use the wire strippers to strip both ends, leaving about a half inch of bare wire.
Take an in-line fuse, with wires attached at both ends, and place it between the cut wire. Twist one end of the horn wire to one end of the in-line fuse wire by hand. Twist a wire nut on the joint. Do the same to the other end, but add the long kit wire into the joint, twisting three wires together and twist a wire nut onto the connection . You now have one single wire connected with two wire nuts, with a fuse in between, and a new hot wire coming out of it. Tape any excess wire slack to the main wire loom.
Run the single kit wire up the loom, taping it to the loom with electrical tape as you move toward the back of the engine. Find a grommet in the firewall and push the wire through. Go to the driver's seat and decide where to mount your horn button. Drill two holes that match the width of the button mounting frame in the metal part of the dashboard. Drill one more larger hole in the centre of the two mount holes. Be careful not to drill into any component on the other side of the dashboard.
Run the wire up through the middle hole toward you and fasten it to the wire on the horn button. You might have a female jack on the button wire or a spade connector. Use the kit parts to join the two wires by stripping the end of horn wire and attaching the proper connector. Once connected, align the horn button-mount over the drill holes and twist two self-tapping screws into the dashboard by hand. Tighten the screws with a Phillips screwdriver.
Connect an additional wire to the back of the horn button if it has two post connectors. This will be a ground wire. Run the ground wire inside the dash board. Crimp a screw eyelet on the end of the wire. Look for a good ground source underneath the dash, such as a small nut or bolt attached to the frame. Remove the bolt with a socket or use a screwdriver to remove the screw. Connect the eyelet to it, and screw the bolt or screw back in with a socket or screwdriver.
Tuck up any excess wire into the dashboard, securing it with electrical tape so it does not fall down or snag on anything. Reconnect the negative battery cable and test the horn operation.
As an alternate method you can connect the horn button hot wire up to the fuse or relay in the fuse block. But to do so properly, you might need to solder such a connection instead of using wire nuts.