Honking a Car Horn: What You Need To Know

Written by

CarParts.com Research Team

Automotive and Tech Writers

Updated on March 5th, 2024

Reading Time: 4 minutes
Summary
  • An electric car horn works using a solenoid attached to a metal diaphragm that vibrates when a current is passed through the solenoid. The vibrations create the sound.
  • Causes of a faulty car horn include a blown fuse, contact point damage or corrosion, and a malfunctioning horn switch or button.
  • You can expect to pay anywhere between $20 and $90 for a brand new horn. It’s best to leave more modern car horn issues to a professional mechanic, but you can follow the tips in this article if you’re looking to repair a vintage horn.
  • The laws regarding car horn honking differ from state to state. In Texas and California, the law instructs citizens to only use their horns when “necessary to ensure safe operation.”

Your car horn has probably seen a lot of use. Its sound serves as a signal to other drivers, a warning for pedestrians, and maybe, sometimes, an outlet for letting off steam. But there’s more to these automotive sound-makers than meets the eye.

How Do Electric Car Horns Work?

The modern electric car horn works using a vibrating metal diaphragm. A car horn is made up of a solenoid and a thin, spring steel disc. When electricity runs through the solenoid, it exerts a magnetic force that reacts with the metal disc to make it flex concentrically. As the diaphragm flexes, it moves the electrical contacts apart, which cuts power to the solenoid.

The contacts close again as the disc returns to its original shape, returning current to the solenoid and repeating the cycle. The steel diaphragm’s flexing and de-flexing cause rapid vibrations that can’t be seen with the naked eye. These vibrations produce the sound of the horn. You can touch the horn when it’s working to feel these vibrations through your fingers, but remember to protect your ears with ear plugs if you do this.

Changing the size of the horn also changes the decibel and pitch levels of its sound. This includes tweaking the spring stiffness, the distance traveled by the disc as it vibrates, and the diameter of said disc. “Two-tone” car horns, which are two units with different tones, are a staple in many cars. Two-tone horns are louder and have a lower tone than the single horns used in motorcycles and small cars.

Causes Behind a Faulty Car Horn

Now, if your car horn is broken, there are a number of causes that might be to blame. These include the following:

  • A blown fuse
  • Contact point damage or corrosion
  • A malfunctioning horn switch or button
  • Faulty wiring
  • Physical damage
  • Mechanical seizure due to corrosion
  • A weak or dead car battery
  • Electromagnet coil burnout

Whatever the cause, it’s important to have a faulty car horn repaired right away. It’s an important tool for conveying urgency or danger when you’re behind the wheel, and not having a functional horn at a critical moment might lead to a bad accident.

How To Fix a Vintage Car Horn

It’s often a good idea to hire a professional mechanic to fix your modern car horn. They’re more difficult to fix by yourself. Vintage, pre-1965 car horns are a little more forgiving because they have removable covers that allow access to their electromagnet and contact points. Parts for these older horns are a little difficult to find though, so it’s important to find a good core if you’re looking to repair one. You can also try the following tips to fix a faulty vintage horn:

Clean the Contact Points

The contact points in a vintage horn need to be clean if it’s going to sound properly. Dress the outer contact points with a file followed by some emery paper. Blow out any resulting debris with dry compressed air. The inner contact points are a little more tricky to clean and should be left to a professional.

Use a Hammer

If the horn’s components are fused together by rust, you can try using a hammer to tap loose the different parts. Just be careful not to dent the metal

Lubricate the Mechanism

To displace moisture while also lubricating the mechanism, you can apply some WD-40 between the different parts. This should leave behind nice working parts.

Disassemble the Core

To access the core of a vintage horn, you might need to disassemble the outer shell by grinding off the rivets that hold it closed. After you’re done, you can close the horn up by hammering new rivets into place.

Adjust the Adjustment Screw

You can adjust a vintage horn’s pitch by twisting the adjustment screw. Tighten it clockwise for a higher pitch, and loosen it counterclockwise for a lower pitch. This won’t make as much of a difference as a different horn body, but it will affect the pitch.

Test the Horn

To test a vintage horn, attach a positive lead to the terminal and a negative ground to the horn’s bracket. Secure the horn using a bench vice before doing this and be prepared for the loud noise and violent vibrations that will erupt the minute the contact points close.

Is It Illegal to Honk for No Reason?

The laws regarding car horn honking differ from state to state. In Texas and California, the law instructs citizens to only use their horns when “necessary to ensure safe operation.” The law is in place to avoid the noise pollution that results from overuse of the horn and to avoid an increased likelihood of crashes.

In general, it’s a good rule to use your car horn only when a pedestrian is in danger, when a car in front of you isn’t paying attention to a stop light, and when a car crash is imminent. Avoid using your car horn when other options are available and when you’re upset and looking to voice your frustrations. In the end, car horns are a great tool for any driver, but you need to know when to use them.

Where to Get a Quality Replacement Car Horn

A faulty car horn isn’t exactly a very pressing matter, but it can cause its own share of problems. For example, if you need to alert another vehicle suddenly, you won’t be able to if you have a faulty car horn. This can prove rather dangerous, especially in emergency situations . Thankfully, you can order a new horn easily at CarParts.com.

CarParts.com’s easy-to-navigate website is built for convenience. In just a few easy clicks, you can order a new horn for your vehicle. Our built-in vehicle selector can narrow down our wide selection of horns to those that will fit your car perfectly. Check out safely and conveniently and we’ll have your order delivered to your door in as fast as two business days. For any questions or concerns, you can reach out to our friendly and helpful customer service team, who offer support around the clock.

Replace your car horn as soon as possible. Place your order for a replacement car horn at CarParts.com today.

About The Author
Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.