The car horn is a safety device that alerts other drivers or pedestrians in the area. It’s composed of circuits and other components that work together to create a loud sound. One of the crucial parts of an electric car horn is the horn relay.
What Is a Horn Relay?
Like any other relay, the horn relay (on vehicles that have a relay) is an electromagnetically controlled switching device.
How Does a Car Horn Create Sound?
The horn converts electrical signals to sound using electromagnetism and a metal diaphragm within the horn.
The relay is triggered to send power to the horn either by a switch or by the body control module (BCM) that receives switch input and responds. Some horn relay circuits are built into the module and there is no separate relay.
Electricity follows one path in the circuit, and the horn button is a normally open switch. Closing the relay triggers the relay, which delivers power to the horn(s).
What Are the Symptoms of a Bad Horn Relay?
To begin with, usually if the horn doesn’t work, the horn itself will be the cause, since it’s in a hostile environment and is doing the heavy work. But the horn relay can also fail.
If you can put your finger on the relay and feel it click when the horn is applied, that means the relay coil is good and activity is taking place. But the relay contacts can still be faulty enough to prevent power from being delivered to the horn(s). That being said, the horn isn’t a very heavy load, and the relay won’t typically fail unless it has been wet on the inside or some ants get in there (this does happen, by the way).
If you can put your finger on the relay and feel it click when the horn is applied, that means the relay coil is good and activity is taking place. But the relay contacts can still be faulty enough to prevent power from being delivered to the horn(s).
– Richard McCuistian, ASE Certified Master Automobile Technician
If you can find the horn and you have a test light, you can see if there is power being delivered to the horn while an assistant attempts to activate the horn with the switch.
Car Horn Stuck On
On older vehicles, a problem with the horn switch is typically the reason for a stuck “on” horn.
A short-to-ground on the control circuit can also cause unwanted horn activation. Since the horn is making the noise, you can usually find the horn and disconnect it if you can get to it. If you can’t get to the horn, you can disconnect the horn fuse or remove the relay if you know where these components can be found.
Horn Doesn’t Work at All
Again, a bad relay is one possible reason why your car horn isn’t working. If you’re not sure if the relay is to blame for your silent horn, take your vehicle to an auto repair shop for a proper diagnosis.
Is It Illegal to Drive Without a Car Horn?
Most states make it unlawful to drive with a broken horn. In California, for example, the law states that a vehicle must always have a fully functional car horn. Vehicles with mandated vehicle safety inspections will require the horn to work during the inspection. And while states like Alabama have laws requiring every vehicle to have a working horn, that state doesn’t require vehicle safety inspections, so the horn law isn’t typically enforced the way inoperative exterior lamps are.
The horn is considered in good working condition if it can be heard from a distance of at least 200 feet.
Driving with a bad horn, whether it’s illegal or not in your area, is dangerous. When there’s an emergency, you’ll need it to alert drivers and pedestrians that you’re in a hurry or need assistance. A good car horn can also help you avoid an accident while driving.
What to Consider When Buying a Horn Relay Replacement
Experts advise buying a car horn that has the same tone as your factory horn. Check the number or letter on the body of the horn to identify the horn’s tone. Also, remember to check your state laws for car horn decibel limits. Most states have a limit of 110 decibels for street horns.
Finding the Best Horn Replacement Replacement For Your Ride
There are many aftermarket horn relays on the market, so finding an affordable one that suits your needs is a breeze. If you have a manufacturer you already trust, consider getting a horn relay from that brand. There’s also no shortage of options if you want to replace the horn itself.
How to Get a Quality Replacement Horn Relay
A faulty horn relay will likely lead to issues with your car horn. Whether it’s causing your horn to honk uncontrollably or preventing it from honking at all, it’s likely best to replace your bad horn relay as soon as you can. Thankfully, you can order a new one at CarParts.com.
CarParts.com has a wide selection of parts from the most trusted manufacturers in the industry at different price points to suit any budget. Placing an order on our easy-to-navigate website is quick and convenient. In just a few clicks, you can checkout and order the parts you need without ever leaving the comfort of your own home. We’ll also have your parts delivered to your doorstep in as fast as two business days, thanks to our strategically located warehouses across the US.
Get your car’s horn working again immediately. Order your replacement horn relay at CarParts.com today.
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