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HomeTips & GuidesHow to Wire a Horn Relay: Wiring Common Horn Relays

How to Wire a Horn Relay: Wiring Common Horn Relays

Know how to wire a horn relay from this guide featuring all the necessary information. 

Many people often use a 4-pin relay in their car horn system. While it works pretty well, we’ll introduce you to a new type that is even easier to install. It is a specially designed horn relay that significantly improves your system’s functionality. 

So, without more ado, let’s see the details. 

How to Wire a 4-Pin Horn Relay?

For many people, the 4-pin relay is the most convenient component for the car’s horn system. Primarily, it’s because the 4-pin relay is easy to wire, as you can see from the circuit diagram below: 

The table below illustrates how to make the connections. 

4-pin Relay TerminalConnect to?
30Battery’s +ve Terminal
85Battery’s -ve Terminal
86System’s Switch
87Horn’s +ve Terminal

How About the 5-pin Horn Relay?

A Horn Relay. 

A Horn Relay. 

The alternative to the above horn relay is the 5-pin type. You can identify it from its extra pin, denoted 87a. We don’t recommend using this relay because the additional terminal complicates the wiring. 

Instead, go for a specially-made horn relay instead of the 5-pin relay, as installing it is more straightforward. Also, since it is a proper horn relay, it has better functionality, and you can install it in a few steps. 

All you need to understand is the wiring procedure, which we have covered below. 

Special Horn Relay TerminalsConnect to?
B+ve Battery Terminal
G-ve Battery Terminal
H+ve Horn Terminal
SHorn Relay Switch

How the Horn Relay Works

Car Relay. 

Car Relay. 

If you set the circuit correctly, as we’ve illustrated above, your system should work perfectly. Also, the working principle of the horn relay is simple: when you press the horn button, a low current flows from the switch to the relay. 

In turn, the relay boosts the signal to a current sufficient to run the horns at the end of the circuit. Thus, when your horn relay is faulty, it lowers the efficiency of the entire horn system. Among the signs to inform you that the relay is not working include: 

  • There is a clicking sound when you press the horn. It indicates that your relay receives current from the steering wheel button but can’t boost it efficiently. 
  • Also, if your horn doesn’t work at all, the relay could be the primary cause. 
  • Thirdly, you can test the relay’s terminals to see a current flow/resistance. If no power transmits across it, it’s probably time to replace it with a new one. 
  • In addition, you can install another horn relay in place of the one you suspect is faulty. If the new relay works well, the former is the problem. 

Car Horn Relay FAQs

Honking a car. 

Honking a car. 

Do you need a Horn Relay for a Motorcycle?

Yes, because it doesn’t matter whether you’re dealing with a car or a scooter’s horn. All types require a relay since the component is cardinal to power supply control. Therefore, it will receive the signal from the switch and boost it to the ideal levels for the horn. 

Can I couple a Horn Relay with a Fuse?

While it is not a primary requirement, we advise installing a fuse between the switch and the relay. It is a safety measure to ensure the relay remains in good shape during a current surge. 

The fuse will blow rather than the entire horn system in this case. Our recommended fuse for the horn relay system is a 5A type. But enquire further from your mechanic on the ideal fuse. 

Will my Horn Work Without the Relay?

Yes, it will. But we don’t recommend not using it because of the following crucial advantages of the component: 

  • First, the simple horn relay is crucial in managing the load on the system’s wiring and the switch. In turn, this extended the use time of these components. 
  • Also, a relay is central to your horn’s consistent and steady power supply, guaranteeing efficiency. 

Wrap Up

When choosing a car horn relay, avoid the hecticness of the 5-pin type by using the specially designed horn relay. It will prove easier to install and has better efficiency as it’s tailor-made for the horn. That’s all for now, but if you have trouble installing your relay, talk to us anytime

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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