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Why is My Car Horn Broken or Not Working

Created on: 2019-02-19

How a horn works and shows the warning signs of failure. This video applies to any vehicle.

  1. step 1 :Diagnosing the Horn
    • Find the location of the fuse box and check the fuse
    • Have an assistant press the horn and listen for clicking from the relay (this means every component up to the relay is working)
    • Locate the terminals on the horn
    • Wiggle the connectors as an assistant presses the horn and check the connectors for corrosion
    • Ground the test light to the negative battery terminal
    • Have an assistant press the horn and check for battery positive at the connector (positive wire is usually the lighter of the two)
    • Check the wires for splitting or breakage
    • Check the clock spring underneath the steering wheel
    • Check the horn switch

What's up, guys? I'm Andy from 1A Auto. In this video, I'm going to show you some tips on how to check your horn if it's not working or if it sounds abnormal to you.

So, the horn system consists of the horn button, which is connected to the airbag, which is connected to the steering wheel; connected to the clock spring; connected to the wires, then to the fuse box, then to a relay, then more wires, then to the horn. And there's also battery—positive and negative.

Okay. I know that's a lot. Let's make it simple. So we have the switch, which is the horn button, and then we have the horn, which is the noise. Something in the middle is not connected and that's what we're going to figure out. If your horn sounds different than normal, usually it's because one of the horns is bad. Most vehicles have two horns. They have a low-tone horn and a high-tone horn. One of them goes bad—the horn really sounds different.

The rest of the system is probably okay. All you have to do is replace the horns. When one goes bad it's just a good idea to do them both, because the other one's probably on its way. The first thing you're going to want to check if your horn isn't working is your fuse. Sometimes it's on the fuse panel on the inside of the car. Sometimes it's on the fuse panel under the hood. You can check your owner's manual to find the location of your fuse boxes.

If the fuse is good, the next thing we want to do is check the relay. A relay is a switch that opens and closes circuits when activated with an electrical signal. What you can do is have a friend in the car pushing on the horn while you're feeling around to find a clicking noise, and if it's clicking, that's a good sign, because that means that everything from the relay up to the horn button is probably good.

So, just because the relay was clicking doesn't always mean it's good. It just means that from everything further back from the steering wheel down is working. So, what you could do is—some vehicles use a similar relay for the rear defrost or other components—you can swap the relay and then recheck the horn. If it works after that, you know that it was a bad relay. If the relay wasn't clicking, you can do the same and test it that way as well.

After we check that and it still doesn't work, the next thing we want to do is locate where the horns are and check the terminals on the horns. We can wiggle the connectors while we're having our friend check the horn and disconnect them. See if there's any corrosion or rust on the terminals. Next we're going to want to check for power at the connector. So, what we're going to do is take a test light, put it on battery negative, and have someone pushing the horn button while checking for battery positive at the connector.

Generally, battery positive is going to be the lighter wire, so if there's a black wire and then another color wire, it's normally going to be the other colored wire. As long as you have battery positive there, then you're going to want to check the ground. You take the test light. Put one end of the test light on battery positive and put the other side on the ground on the connector. If the ground's good, everything's good there. You're going to need a horn.

If the battery positive wasn’t there when you were checking that circuit, you're going to have another problem somewhere else. You could have a broken wire. You could have a clock spring that's broken, which is underneath the steering wheel. Or it could be the horn switch itself.

I hope these tips helped you out. As always, if you need parts for your vehicle, click the link in the description and head on over to 1aauto.com.


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