How to Wire an Oogah Hornby Mike Frees
Whether you have an antique jalopy or a modern car, installing an "oogah" horn will attract attention and entertain those around you. Because of the unusual nature of this horn, it's a good idea to install it as a second horn with a separate button, leaving your original horn available for normal use. If the horn kit you purchase does not include a horn relay and button, you will need to buy a horn button kit.
Locate a place under the hood away from the exhaust manifold or moving engine parts. Drill a 1/4-inch hole and mount the horn with the trumpet pointing down (to prevent moisture from accumulating in the horn) using the bolt, nut and lock washer that came with the kit. Connect the negative terminal of the horn to a ground wire attached to a bare metal component with a sheet metal screw.
Install the horn relay near the horn. The horn relay is typically attached with a single self-tapping or sheet metal screw, which should be included in the kit. Connect the positive terminal of the horn to the appropriate terminal of the relay as indicated in the relay instructions.
Find a good spot for the horn button on or under the dashboard or on the steering column. Attach the button using the hardware provided. One wire from the button should be attached to a bare metal ground using a sheet metal screw. The other lead should be routed forward into the engine compartment to the relay. Attach the wire to the correct terminal of the relay as specified in the instructions that came with the kit.
Connect the positive (+) terminal of the relay (as indicated in the instructions) to a 12-volt supply. If a spare 20-amp fuse is available in the engine compartment's fuse box you can use that. Otherwise, you can connect the wire directly to the positive terminal of the battery, but you must also connect a 20-amp inline fuse into the circuit.
Test the horn. If it does not sound, reverse the two wires connected to the horn and test again. When the horn sounds correctly, secure any loose wires with cable ties or electrical tape to finish the job.