If your car horn is not working or it sounds abnormal, such as a broken high horn, there are a few parts you can check in the horn system to tell what is the cause. This post explains how to test a car horn system if the horn stopped working as usual.
How to Check a Car Horn That Stopped Working
How to Test a Car Horn Not Working
What Parts Are in the Horn System?
The horn system includes the horn button, which is connected to the air bag and steering wheel and also the clock spring, wires, fuse box, relay, horn, and positive and negative battery terminals.
Why Has My Car Horn Stopped Working?
If the horn is not working or sounds off, a component in the horn system is not connected, meaning there is a disconnect between the horn button on the steering wheel and the horn at the front of the vehicle.
Usually, if the horn sounds off, it’s because one of the horns has worn out. Most vehicles have two horns: a low-tone horn and a high-tone horn.
Usually the repair consists of removing parts like the grille to access the horn, loosening the bolt from the horn, and disconnecting the horn electrical connector.
This video shows some common steps for replacing a bad horn.
Steps for Testing a Car Horn Not Working
1. Test the Horn Fuse
Sometimes the fuse for the horn is in the interior fuse panel and other times it’s in the fuse panel under the hood. Check the owner’s manual to find location of the fuse boxes.
The fuse can be tested for a connection with a test light, and it can be removed and inspected for a broken wire.
2. Test the Horn Relay
If the fuse works, the next step is to check the relay. The relay is a switch that opens and closes circuits when activated with an electrical signal.
How to Test a Horn Relay
- Have an Assistant Press the Horn and Listen for a Clicking Noise
Have an assistant press on the horn in the car and listen for a clicking noise like heard in the video above at 1:43. If there is a clicking noise, that is a positive sign since everything from the horn button on the steering wheel to the relay is likely working.
- Swap the Horn Relay with a Similar Relay
To test the relay, try swapping it with a similar working relay. Relays like the rear defrost can be swapped with the horn relay. Then test the horn and see if it works. If the horn is defective, the relay is bad.
3. Test the Horn’s Electrical Connector
Wiggle the Electrical Connector
Locate where the horns are. Try wiggling the connector as an assistant presses the horn to see if that affects it. Check the electrical connector’s terminals for rust or corrosion.
Check the Electrical Connector’s Positive Terminal with a Test Light
Then check the electrical connector with a test light. Connect the test light to the negative battery terminal and connect the test light to the positive terminal connector, which is usually connected to the lighter-colored wire. Have an assistant press the horn. If the test light illuminates, the positive connection is good.
Check the Electrical Connector’s Ground Terminal with a Test Light
Next, check the ground. Place an end of the test light to the positive battery terminal and connect it to the negative terminal on the electrical connector, which is usually connected to a black wire. If the connection is good, the horn needs to be replaced. If the connect is bad, there is a problem elsewhere like a broken, torn, or frayed wire, a broken clock spring, or a broken horn switch.
Fix a Broken Horn Yourself
Fix a broken horn on your vehicle with tons of how-to videos with instructions for repairs on many makes and models.