How to Wire a Wolo Horn

by Thomas West

Wolo horns are available as aftermarket accessories for most vehicles from over the road semi trucks to your everyday car. Wolo has been in business since the mid nineteen sixties and is a major producer of all types of horns, including train horns and musical horns that play popular tunes such as Dixie or La Cucaracha. A Wolo can be installed as a supplemental horn or can completely replace your vehicle's factory installed horn. Installation is straight forward and can be completed with regular tools in a short time.

Install the horn relay (included with horn kit) near the horn compressor with the electrical connectors pointing downward. Hold the relay in the desired location and use a pencil to mark the relay's mounting holes. Set the relay aside and use an electric drill with a 1/8 inch drill bit to drill holes in the marked area. Attach the relay by turning in the attaching screws (included with horn kit) in a clockwise direction with a Philips screw driver.

Mount a horn button (not included with horn kit) in the desired location inside the passenger compartment using the instructions that come with the horn button.

Connect the horn relay terminal marked "87" to the positive terminal on the horn compressor with the wire included by pushing the wire connectors onto the terminals by hand.

Connect the horn relay terminal marked "85" to the horn button terminal with the wire included by pushing the wire connectors onto the wire terminals. Connect the ground wire from the horn button (included with the horn button) to a metal part of the vehicle's body under the dashboard. Drill a hole with a drill and 1/8 inch drill bit and attach the wire to body using the screw provided.

Connect horn relay terminals marked "30" and "86" to a twelve volt power source in the vehicle, such as the accessory slot in the vehicle's fuse box. Connect the wire connectors to the wire terminals by pushing them on by hand. Connect the other end of the wire to the fuse box using a fuse box terminal adapter (available at auto parts stores).


  • check If the supplied wires with the horn kit or horn button are not long enough for your application, replace the wires with 16 gauge automotive wiring available in auto parts stores. Wiring may be available for purchase by the foot or sold in precut spools available in several different lengths.
  • check If you are replacing your vehicle's original horn with a Wolo horn, do not use the relay supplied with the Wolo horn kit. Merely connect the Wolo horn to the vehicle's original horn wiring connectors.

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