Learning, Wiring,

How to Wire Air Horn with Diagram? (4 Steps)

Do you need some help wiring an air horn for your car?

Installing a new air horn on your car could be easy, but the wrong execution can blow a fuse or damage your air horn. Today, I will teach you how to wire an air horn using a relay. This is the safest way; I will use the air horn wiring diagram below to teach you.

In general, to wire the air horn to your vehicle:

  • Gather the necessary equipment.
  • Identify the four-pin relay correctly.
  • Install the air horn in a suitable location.
  • Complete the wiring using the diagram.

Learn more about this process by reading below.

4 Simple Steps to Wire Air Horn Using a Relay

There are several different ways to wire air horns. But wiring it with a four-pin relay is not complicated and guarantees the fuse box’s safety. I use this technique for most air-horn installations and wiring tasks.

Step 1 – Gather the Necessary Things

First and foremost, gather the following things.

  • Air horn
  • 12V four-pin relay
  • Digital Multimeter
  • Different color-coded wires
  • A Few alligator clips

Step 2 – Identify the 4-Pin Relay

After collecting all the necessary things, you can inspect the four-pin relay. Understanding the four pins correctly before you start the wiring process is important.

Tip: Some air horn kits come with a four-pin relay. But this is not true for all air horn kits. Hence, you might have to buy a four-pin relay. Remember to buy a 12V 30A relay for this method.

  • 30 and 87 pins are the power in and out pins.
  • The positive terminals of the 12V battery are connected to pin 30.
  • And pin 87 connects to the air horn’s compressor (positive end). Pin 85 is the ground connection for this operation.

Hence, connect it to any grounding point in your vehicle.

Lastly, pin 86 connects to the signal wire of the vehicle’s horn.

Step 3 – Install the Air Horn

Now you can mount the air horn in a proper location. You can often mount the air horn behind the rail or under the hood. Either way, remember to mount it properly before the wiring process.

Step 4 – Complete the Wiring

After you mount the air horn in your desired location, you can complete the wiring. For that, use the below wiring diagram.

  1. Connect the air horn compressor (positive terminal) to the relay pin 87.
  2. Ground the compressor’s negative terminal to any ground point.
  3. Connect pin 30 to the positive terminal of the battery. Remember to use a suitable fuse for this connection.
  4. Ground the relay pin 85 (use negative battery terminal)
  5. Connect pin 86 to the vehicle’s horn (signal wire).
  6. Double-check all connections according to the wiring diagram before testing the air horn.


Is It Possible to Wire an Air Horn Without a Relay?

Yes, it is possible to wire an air horn without a relay. However, a relay is the most suitable method since it protects your air horn and vehicle components.

With that in mind, here are a few simple steps to wire an air horn without a relay.

  1. Mount the air horn in a suitable location.
  2. Ground the negative terminal of the air horn compressor.
  3. Connect the compressor’s positive end to the signal wire and the 12V battery (positive terminal).


What Gauge Wire for an Air Horn?

Depending on the type of air horn, you can use 12-16 gauge wires for the air horn wiring process. I use a 14 gauge wire for all connections.


Can I Install an Air Horn on My Pickup Truck?

Yes, indeed. You can install an air horn on a pickup truck. An air horn is an important part of a pickup truck since it is a large vehicle. Also, you can install the air horn anywhere in the truck. Compared to your car, the pickup truck will give you more mounting places for air horns.




Video Reference

Strange Garage

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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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