How to Replace a Horn Relay

Car horns are used for a variety of purposes, not least among these safety. For a car horn to work properly, the vehicle must be equipped with a functioning horn relay.

typical horn diagram

In most circuits, when the horn button (usually located in the steering wheel pad) is depressed, power is allowed to flow through the horn relay to the horn assembly. Typically, there is power supplied to the horn relay at all times. Pushing the horn button completes the ground side of the circuit, pulling the relay contacts closed and causing the horn to honk.

A bad or failing horn relay probably requires replacing. Follow this step-by-step guide to learn how to perform this repair.

Part 1 of 2: Removing the old horn relay

In order to safely and efficiently replace your horn relay, you will need a couple of basic tools.

Materials Needed

diagram of a junction or fuse box

Step 1: Confirm the location of the horn relay. Typically, the horn relay is found in the engine compartment junction or fuse box. Consult your owner’s manual for the exact location.

hand disconnecting the negative battery cable

Step 2: Disconnect the negative battery cable. Open up your vehicle’s hood and disconnect the negative battery cable with a wrench or ratchet. Then set it aside.

hand removing the junction lid box

Step 3: Remove the junction box lid. Locate the junction or fuse box within the engine compartment and then remove the lid.

removing horn relay

Step 4: Remove the old horn relay. Remove the horn relay by pulling it straight out.

Part 2 of 2: Installing the new relay

hand installing the new relay

Step 1: Install the new relay. Install the new relay by lining up the terminals with the slots in the junction box and plugging in the relay.

junction box lid being replaced

Step 2: Reinstall the junction box lid. Replace the lid on the junction box.

Step 3: Reconnect the negative battery cable. Reconnect the negative battery cable and tighten it down.

After following these steps, you should now have a horn that blows nice and loud. If you’d prefer to have a professional tackle this task for you, the certified mechanics at YourMechanic offers expert horn relay replacement service.

Next Step

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35 years of experience
731 reviews
35 years of experience
Nissan Altima L4-2.5L - Horn Relay Replacement - Phoenix, Arizona
William was a informative and quick mechanic. His knowledge of the parts and install were great. He even took the time to explain what he did. I would recommend him to anyone
Ford Edge - Power Steering Pump - El Mirage, Arizona
First time using mobile mechanic and very happy. William arrived on time, very courteous and knowledgeable, William completed a very difficult Power Steering Pump replacement no problem! Looking forward to having him back and very happy I decided to use Your Mechanic for our repairs.


34 years of experience
441 reviews
34 years of experience
Chevrolet K1500 Suburban V8-5.7L - Horn Relay - Sacramento, California
He was on time and very courteous I am waiting for him to come back to ensure that my truck will pass smog as he gives clear and concise instructions on what I am to do


18 years of experience
35 reviews
18 years of experience
Jeep Grand Cherokee V8-4.7L - Horn Relay Replacement - Auburn, Washington
Only chatted real quick, I had work, handed him the keys and it was fixed. While at work I received photos and a summary of what was done including audio. This was my fist time using yourmechanic, works great especially as an introvert, I hate going out in public (war brain thing) so this really takes the edge off


39 years of experience
607 reviews
39 years of experience
Subaru Impreza H4-2.0L Turbo - Horn Relay - Denver, Colorado
Scott was very pleasant and explained everything to me..

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