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How to Wire a Car Horn

by K.K. Lowell

Wiring a horn the right way, whether to replace a non-working horn, or to install a new one to a custom vehicle is a job that a competent do-it-your self type should be able to complete in an hour or two.

Disconnect the negative terminal from the battery.

Using the self-tapping screw, mount the 20-amp circuit breaker in a protected location near the vehicle battery.

Connect one terminal on the circuit breaker to the positive terminal of the battery, using a piece of wire and two solderless ring terminals.

Connect the other terminal of the circuit breaker to Pin 87 of the Signal Stat 192 relay. Use a length of 14-gauge primary wire with a ring terminal on the circuit breaker end and an insulated solderless spade terminal of the relay end.

Connect Pin 87a and Pin 86 with a short piece of 14-gauge wire, having a female solderless spade connector on each end.

Mount the horn. Use a large self-tapping screw, and mount to an area behind the bumper or grille.

Connect Relay Pin 85 with the terminal on the horn, using a length of 14-gauge wire with solderless female spade connectors on both ends.

Mount the momentary contact switch within easy reach of the driver.

Connect Relay Pin 30 with a terminal on the momentary contact switch. Use 14-gauge primary wire.

Connect the other terminal of the switch to a metal part of the vehicle.

Reconnect the battery's negative terminal.


  • If your replacement horn has two terminals, the other terminal is to be connected to a metal part of the car or the negative terminal of the battery.

Items you will need

About the Author

K.K. Lowell is a freelance writer who has been writing professionally since June 2008, with articles appearing on various websites. A mechanic and truck driver for more than 40 years, Lowell is able to write knowledgeably on many automotive and mechanical subjects. He is currently pursuing a degree in English.

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