Of all the safety features in modern cars, the car horn is one that most people take for granted. Yet, it’s the sound of a car horn that warns pedestrians and other road users, helping keep cars, people, and even animals safe while on the road.
Finding a dead car horn when you need it most can be a hair-raising experience. You need to check for a blown fuse, loose/damaged wiring, or a faulty relay. Older cars are more likely to have a worn-out horn or a defective switch in the steering wheel.
Resolving a dead car horn is straightforward and affordable compared to other repairs. So, read this guide to understand why yours failed and how to fix each cause.
Why Isn’t My Car Horn Working?
A car horn stops working for various reasons. Here are some of the common causes of a problematic car horn and the fixes necessary to get it working again.
1. Blown Fuse
The most important thing to remember about your car horn is that it's an electrically powered component. That means it needs a continuous and reliable electricity supply to function correctly. It also means that anything preventing the electrical current from reaching the horn unit will stop it from working.
That’s why the first and most common reason for a dead car horn is a blown fuse.
A fuse is a sacrificial device, which means it will destroy itself to protect the electrical circuit. There are plenty of electrical circuits in your car, so the vehicle has a box full of fuses.
When the fuse protecting the car horn’s electrical circuit blows, no electrical current will flow to the horn. As a result, you won’t hear the sound of a car horn no matter how hard you push the button on your steering wheel.
How to fix it: As you read above, a fuse is a sacrificial device that destroys itself to protect the circuit from an electrical fault. Unfortunately, that also means the fuse is not serviceable or repairable.
The only solution here is to replace the fuse with a new one. That will restore the flow of electricity to the horn and make it work again.
That seems like a straightforward repair, but there are two things you must remember. Firstly, always use an identical replacement when installing a new fuse.
Secondly, troubleshoot the circuit for the electrical fault that blew the fuse in the first place. This will prevent the problem from happening again and destroying the new fuse.
2. Loose or Damaged Wiring
A dead car horn can also be a wiring issue. More specifically, the wires connecting the horn to its power source could be loose at either end or damaged entirely.
If you’ve worked on the horn recently, the likely reason for the dead car horn is loose wiring. A short circuit could also cause the wires to burn or break off.
Whatever the case, wiring that isn’t intact will stop the horn from working and leave it dead until you fix the issue.
How to fix it: Firstly, you must inspect the horn’s wiring. You can easily fix loose wiring by reattaching it tightly, but damaged or burnt wiring must be replaced entirely.
3. Worn-Out Horn
Like any other component in your car, the horn can also wear itself out. An older unit will eventually stop working from normal wear and tear.
Habitually using the horn (read: excessive honking) can also prematurely wear out your car horn.
How to fix it: Once you rule out other possibilities and find that your horn is worn out, the only solution is replacing it with a new one. You can get an OEM unit or an aftermarket one like a Bosch car horn.
4. Faulty Relay
Another electrical component that can jeopardise your car horn is the relay. A relay is a switch that controls (or 'relays') the flow of electrical current to components like the car horn.
Relays are electrically powered but have mechanical parts inside that can stop working correctly, interrupting the flow of power to the car horn.
As a result, you get a dead horn that doesn’t work when you need it to.
How to fix it: Electrical relays are replaceable in the same way that fuses are. So, suppose the one connected to your car horn stops working, you only have to remove it and install a compatible replacement.
5. Failed Horn Switch
If you’ve ruled out all other possibilities, the likely cause for your dead horn is a failed horn switch. That’s the switch on the steering wheel that you press to activate.
Without a working switch, the car horn never gets the electrical current it needs to produce sound.
How to fix it: As you can imagine, the failed switch must be replaced. However, it’s best to let a qualified technician do it for you because the switch is a part of your steering wheel where the airbag is also located.
How Do You Know When a Car Horn Is Failing?
A dead car horn doesn't always happen without warning. There are symptoms to let you know in advance that the horn is reaching the end of its useful life.
Here are some signs that your car horn is failing or about to go dead:
- Tone change: Firstly, you might notice that your car horn’s tone has changed for no apparent reason. That change suggests the horn is no longer working optimally and might die soon.
- Low volume: Aside from tone changes, a drop in volume is another symptom of a dying car horn. Granted, you don’t need to have the loudest legal car horn in Australia, but your horn should never drop below its usual volume.
- Intermittent working: Lastly, a car horn that alternately works and fails is about to die. For example, nothing happens when you use it, but suddenly you have a loud car horn the next time.
When you notice one or more of these signs, you’d best have someone troubleshoot or replace the horn to save you the trouble later.
Where Can I Buy a New Car Horn?
You can buy OEM and aftermarket car horns from online or in-person sellers. However, considering how car horns can sound different from one another, it’s best to find a place that lets you test them first.
Find a nearby auto accessories dealer by browsing the CarpartAU Directory. You can gather their contact details and call them to see if they have what you need.
By Ray Hasbollah