CAR HORN-HOW TO FIX-TEST-REPLACE-ADJUST AND MORE

how-to-fix-car-horn.

Car horn is one of the most important parts of the car in terms of signalizing.

Sound signals are equally important as visual ones in everyday traffic. So having a faulty car horn is both dangerous and annoying. When a traffic situation comes up and you need the car horn, it will be like you turned mute on the TV.

In this article we’ll try and help you fix this problem. In most cases it’s a DIY job and not that complicated. Although the repair was done on a Skoda Fabia mk1, you can apply the same principle to whatever car you drive.


CAR HORN WIRING DIAGRAM-HOW DOES A CAR HORN WORK?

Before we start, just a few words about the car horn basics. This will perhaps help you solve the problem more easily.

If you have the time, click here for a great explanation on Wikipedia on how the car horn actually works.

Lower you have two basic car horn wiring diagrams which will, hopefully, help you understand more about how everything functions.

  • Basic car horn wiring diagram without relay (it can be different, the horn switch can cut the positive “+” connection instead of the ground connection).

 car-horn-wiring-diagram

 

  • Basic car horn wiring diagram with relay-most common in today’s cars. The relay safeguards the car wiring and installation from overload, especially if there is a more powerful car horn.

 car-wiring-diagram-with-relay

 

 


 

MAIN SYMPTOMS OF A FAULTY HORN

These are some of the main symptoms which you’ll come across when the car horn isn’t working:

  • When you press the horn switch nothing happens
  • Car horn not working-only clicking sound appears
  • When pressing the horn switch the car horn sounds weak.
  • The car horn won’t stop working

We’ll go in to detail for each symptom, cause and possible solution lower in the article.


 

WHY DOES A CAR HORN STOP WORKING?

Listed below are the common problems regarding car horns.

  • BLOWN FUSE

 car-horn-find-blown-fuse

This usually happens if there is a short-circuit in the electric system (wiring, perhaps a faulty relay or the car horn itself). Also, a blown fuse can happen if the car horn is used extensively (like long,uninterrupted continuous usage).

If the car fuse is blown and you don’t know how to change it, click here for a separate article on that topic.

  • BAD-DIRTY CONTACT, LOOSE CONNECTION, BROKEN OR DAMAGED WIRES

car-horn-how-to-fix-bad-contact wire-harness-connection-car-horn

Although most car horn connectors are quality made and have protective rubber or plastic around them, sooner or later moist and filth can get inside and cause corrosion which means lack of good contact.

This is especially present if the car horn is in an exposed location or an aftermarket one was installed that doesn’t have enough protection for the contacts.

Broken wires can also cause problems although more rarely. This usually happens if there was physical damage or the wiring was heavily bent (like near the connector).

  • HORN SWITCH IN THE STEERING WHEEL

car-horn-pressing

Horn switches are incorporated within the steering wheel. It’s a basic switch activated by pressing it against the wheel. The contacts of the switch are separated by springs which are embedded between the switch and steering wheel.

There are different designs and solutions. Some switches are in the central part of the steering wheel, some are on the sides. Most of them are of sturdy design so they don’t usually cause problems. Again, highly depending on the type of switches.

  • FAULTY CAR HORN

faulty-car-horn

Original car horns (ones from the manufacturer) usually last for most of the cars “life “unless they suffer some kind of physical damage or else.

Nevertheless, over time, mostly due to material fatigue or poor quality, they can malfunction. Mostly what happens is that the membrane inside the car horn wears out (tears) or the electromagnetic coil gets damaged-burns out.

  • DIRT AND FILTH GETS INSIDE THE CAR HORN

As the car horn is located in the engine bay it is highly susceptible to dirt and filth. Although manufacturers do a good job in protecting the car horn by putting them in protected places (bumper or front grill) overtime it gets dust, dirt and moist inside.

One of the most common reasons why people replace a good horn is that they make a mistake that it’s “burnt” out when in fact it’s just stuck because of filth. This can be solved by adjusting the car horn; more about that lower in the article.

  • FAULTY CAR HORN RELAY

 car-horn-relays

The main task of a horn relay is to take off the burden of high electric current from the horn switch and the rest of the electric installation.

If you want to see how a relay actually works, click here for a great explanation on Wikipedia.

This fault is pretty rare. The car horn is used occasionally so the relay should last pretty long. Nevertheless, always worth the check.

  • FAULTY INDICATOR STALK

indicator-stalk

Since the wheel turns, manufacturers had to come up with a system of how to connect the horn switch on the steering wheel with the rest of the electric installation.

This was solved by making a connector ring on the steering wheel and a connecting surface on the indicator stalk. The ring slides constantly over the connecting surface giving permanent connection while the wheel is turning.

Most problems appear when the connecting surface (in most cases looks like a copper tentacle) wears out because of friction and electric contact.

Also a rare problem, as these are made pretty robust and should last for a long time. Mostly causes problems in older, high mileage cars or if the engineering solution is not that good.


 

WHAT TOOLS WILL YOU NEED?

Fixing a car horn problem is not needy regarding tools and most of them you probably already have around the household:

  • Tester or a multimeter

multimeter-electric-tester

  • Pliers-combined ones would be best

car-tools-pliers

  • A pair of jumper cables or some wire with connectors (this is for testing the car horn)

jumper-cables

  • 12 V power source (car battery, battery charger or else)

 

car-battery-charger

car-battery

  • New or working car horn

 how-to-fix-car-horn.

  • Basic set of wrenches, ratchets and sockets

basic-car-tools-set

These are all optional, all depending on what the fault is. You may need only one tool or a combination of these.

One more tip, don’t buy a new car horn until you’re sure that the old one malfunctioned. First test and find what’s really wrong then spend money on a new one.


 

HOW TO FIND THE CAR HORN?

As you’ll see once you begin the repair, on most of today’s cars locating the car horn can be a serious task.

Most manufacturers tend to put the horn in a tucked up place and closest to the outside as possible. This is for better sound and better protection from outer conditions.

Three places you should look first:

  • behind the front grill: usually in the middle lower part

car-horn-location-behind-front-grill-mask

  • inside the front bumper (lower left or right part)

car-horn-location-front-bender-plastic

  • under the front left or right fender plastic

 car-horn-location-under-fender-plastic

 

These are the three most common places. Rarely (maybe in older cars) the car horn is set in a visible place inside the engine bay.

I would advise on this part to Google the topic. It will save you a lot of time, searching and unnecessary disassembly. Just type in your car model and the term “car horn location” and it should pop up.

Most manufacturers choose such a place where only perhaps a plastic lid or cover has to be taken off which is pretty easy. This is the case with the Skoda Fabia.

car-horn-location-plastic-covering

But sometimes (depending on the car model) it won’t be that easy and will involve more serious disassembly and perhaps going underneath the car.

Again, best see where the car horn is located before you start and can you reach it properly. If you can’t, no fix their and you’ll know it on time.


 

HOW TO FIND THE MALFUNCTION THE PROPER WAY?

Quality diagnostics, as with very other car repair, is half the job.

In this case, checking the power supply to the car horn is the beginning point.

This way you divide the problem in to two parts : either it’s the electrical input that comes to the horn (including fuse, relay, horn switch, bad connections or else) or it’s the car horn itself.

This is the proper way to do it:

  • Once you’ve found the location, you’ll probably have to take the horn out. On some cars, if the electric connector can be easily reached, just disconnect it without taking of the horn. If you have to take it out,you’ll find a screw or nut holding a bracket which then holds the horn in place. Unscrew the nut or screw (it will be usually a 10 or 13 mm).This way you’ll be able to pull out the car horn and test it in the open which is much more convenient.

take-off-screw  bracket-screw-removal-scaled

 

  • Disconnect the horn and take it out. It will have a plastic connector or two separate wires.

 disconnect-car-horn-wire-harness

  • Find someone to press the car horn switch since you won’t be able to simultaneously reach the switch and see if there’s a power supply.

car-horn-pressing

 

  • Use the battery tester or multimeter and hook it to the car horn connector. Point here is to make a closed loop (instead of the horn, you’re connecting either the multimeter or tester).
            If you’re going to use a tester, put one side (clamp) in one pin and the tester point in the other pin.
           For the multimeter, put one input jack in each pin. Set the multimeter to 12 V DC current.
           If the connector has small pins, you can use pieces of wire and push them inside to extend the connection.

 electric-tester-for-testing-car-horn  multimeter-showing-volatge-car-horn

  • Press the horn switch. If there is a proper power supply, the multimeter will show voltage (about 12 V). In case of the tester, it will light up if there is a proper power supply. If not, the multimeter will show zero volts and the tester will not light up.

Now you have your starting point.  Once again, if the power supply is OK, the car horn is faulty in some way.

No power supply, begin your search within the rest of the system.

I always use the tester as it is much more convenient (at least for me). Also, cheaper to buy if you don’t have a multimeter.


 

CAR HORN NOT WORKING-MAIN SYMPTOMS AND SOLUTIONS

These are some of the main symptoms and solutions when the car horn isn’t working:

       1.When you press the horn nothing happens

This is the most complicated malfunction. You may solve it in minutes or end up searching and fixing for hours as it may involve checking the whole installation. Start with these:

 

  • Power supply to the car horn

 electric-tester-for-testing-car-horn

If there is a proper power supply, take of the horn and try to adjust it. Adjustment didn’t help?  Then it’s probably time to replace the car horn.

If there isn’t a power supply then check the:

  • Fuses-check these first before dismantling anything,

car-horn-find-blown-fuse

One of the most common reasons especially if you’ve used the horn extensively.

First place to look if there is no power supply to the horn.

If you don’t know how to change a car fuse, click here for a separate article on that topic.

  • Car horn connection (check for a broken, filthy or corroded connection)

disconnect-car-horn-wire-harness wire-harness-connection-car-horn

 

Once you’ve disconnected the horn take a look at the connector(s). If they are corroded and oxidized this could cause a problem. This goes double for pin connectors.

Use some WD-40 spray or other connection sprays and try to clean it. If there is too much damage, best replace the whole connector.

You can either buy a new connector (as same as the old one) or cut the original one out and replace it with separate, old-school type ones. Just make sure to insulate them properly.

The repair will surely last longer if you buy the same connector as the original one.

  • Horn switch on the steering wheel

 car-horn-switch

This problem usually appears gradually.

In the beginning, when pressing, only some parts of the horn switch react (left, right, upper or lower). In time, it stops working entirely.

Simply, the contacts inside wear out or get dirty. Also, if the switch has been subdued to physical damage (like hard pressing or banging) it can malfunction.

You’ll have to take off the car horn switch for this repair. It’s mostly done by either pulling the switch out of the steering wheel or by releasing hinges or screws from the backside of the steering wheel.

Best Google this procedure for your type of car in order to save time and avoid damage.

The car horn switch in most cars is also a casing for the air bag so be careful when taking it off. Keep the ignition turned off or even better take the minus terminal  off of the car battery and wait for 15 minutes or so.

I would advise taking the battery terminal off as it’s the safest. This way you’ll surely avoid the air bag accidentally blowing in your face and injuring yourself.

Once you’ve taken it off, make an inspection of the parts, If there is dust and grit on the contacts and connections, best use a clean cloth, some contact spray or some fine graded sandpaper and clean everything up.

If the switch itself is faulty, best replace it completely, Some switches can be taken apart and fixed but this is mostly on older car models without air bags.

You’ll also find a wire from the switch to the steering wheel, check that connection also.

  • Car horn relay

car-horn-relays

Relays burn out rarely. Mostly if the horn has been extensively used. They can also malfunction due to material fatigue but this happens mostly in older cars.

The most common place for the relay is the fuse box or near it.

Diagnostics is done with a multimeter or tester. Simply pull the car horn relay out and check the embedded connections to the relay. If there’s power input to the car horn relay, then you should probably replace it.

Replacement is simple, pull out the old one and push in the new relay.

  • Electric installation (broken cables, weak connections or else)

 loose-broken-wire-connection

Weak connections and broken cables are known to cause problems, but rarely. Mostly happens if there was some kind of work done around the installation (like taking of the bumper or else).

For broken cables check spots like right behind the car horn connector or parts where the installation is vulnerable (open or bending parts).

Regarding weak contacts, most problems come from connectors (one or more) or weak ground connections.

     2.Car horn not working-only clicking sound appears

Main reason for this is either a faulty car horn or weak power supply.

Clicking sound appears when the membrane or the moving mechanism inside the car horn gets stuck.

Reason for this is mostly filth and dirt getting inside and blocking the membrane from moving.

Solution to this problem is either replacement or adjusting the car horn. More about car horn adjustment lower in the article.

Weak power supply means primarily checking out the car horn switch and the connection between the steering wheel and indicator stalk. Besides that, you can inspect the horn connector and wiring.

   3.Car horn sounds weak

car-horn-adjustement-screw

If you press the car horn switch and you get a weak sound, then you’ll probably have to adjust or replace the car horn completely.

So, before replacing, first try adjusting. Again, more on that lower in the article.

       4.The car horn won’t stop working

indicator-stalk

Maybe you’ve sometimes seen people in traffic or in the parking lot in despair, just waving their hands while the car horn is honking non-stop while they’re not pressing the horn switch at all.

Main reason for this is will be:

  • Stuck or loose car horn switch

As mentioned,horn switches endure significant pressure while using it. Horn switches are held back by springs which may lose strength overtime or break due to material fatigue. Loose parts or weak springs that can’t hold the switch in place can cause an accidental connection and activate the car horn.

This is solved by removing the horn switch and replacing the springs or broken parts.

  • Loose-broken connector on the indicator stalk.

Regarding the indicator stalk problem: the copper contact on the stalk can break off, accidentally connect to the connector ring on the steering wheel and the horn will start honking without control.

If this happens the solution is replacing the indicator stalk. This is a costly repair since the stalks are not cheap. But on most cars, indicator stalks are made out of two parts so maybe you’ll have to change just one part making this mishap a bit less expensive.

Replacement procedure is pretty complicated.  In short, for most cars, it goes like this:

You have to take off the steering wheel in order to gain access to the indicator stalk. After that you have to take off the plastic trimming around the wheel.Then you have to disconnect the stalk, unscrew it of the steering column and take it off.

Returning goes in reverse procedure.

Pretty complicated job and I wouldn’t advise it unless you have at least some experience around cars.

At the end of this part, if you get in a situation where the car horn is honking non-stop the best thing to do, for first aid, is take out the car horn fuse or disconnect the horn altogether (if you can reach it).

HOW TO MAKE A CAR HORN REPLACEMENT?

If you’ve concluded that the car horn has totally malfunctioned, then you have to replace it.

Most horns are held in place by a metal bracket and a single nut or screw. If you have double car horns, the only difference will be perhaps more brackets, screws or nuts.

Anyway, once you’ve gained access to the car horn:

  • On most cars you’ll find a screw or nut holding a bracket which then holds the horn in place. Unscrew the nut or screw (it will be usually a 10 or 13 mm). On some cars you won’t have to remove the horn complete with the bracket, just unscrew the nut on the backside of the horn. Do what suits the situation the best.

  • Unscrew the nut or screw with the proper wrench or socket. Sometimes you’ll have to use extensions like in the picture. Do what suits the situation best.

take-off-screw  bracket-screw-removal-scaled

  •  Take the electric connector off. In some cases you’ll have to pull out the horn so you can reach the connector.

 disconnect-car-horn-wire-harness

  • If the new horn didn’t come with a bracket, take off the old one and mount it on the new car horn. The nuts that hold the bracket can be stubborn so use some WD-40 or some other anti-rust spray.  

bracket-holder-untighten-nut

  • Return the car horn in to place and re-connect it. It would be good to put some contact spray in to the connector.

faulty-car-horn wire-harness-connector

 

  • Properly align the bracket with the anchor on the car. Insert and tighten the nut or screw.

take-off-screw

  • Return plastic lids or coverings (if there were any)

car-horn-location-plastic-covering

If you decide to buy an aftermarket car horn which is not the same as the original one in terms of mounting and electric connections, you’ll have to make a few adjustments.

Namely for the bracket and electrical connector. You’ll perhaps have to do things like bend the old bracket in order for the new horn to fit in.

The old electrical connector may have to be cut out and separate connectors (for each wire) may have to be installed.

Whatever the case may be, it’s not complicated nor demanding and you’ll surely find you’re way around it.


 

HOW TO TEST A CAR HORN?

Once you’ve taken off the car horn, in order to be sure that it’s faulty, you have to test it.

It’s a simple procedure, all you’ll need is a power supply and a connection to the horn.

  • Provide a power supply:car battery, car battery charger, power converter or else

car-battery car-battery-charger

Make sure that the power supply voltage is adjusted to the horn. On a car it will probably be 12 volts, for bigger pick-ups and trucks it can be 24 volts. Take a look before you start so you don’t damage the horn (higher voltage supply will damage or burn out the horn).

  • Make a good connection to the car horn

wire-harness-connection-car-horn

Since most of today’s horns have pin-like connections that are hard to reach, use pieces of wire with connectors on them.

This way you’ll be able to reach and extend the horn connection in such a way that will enable you to connect the power supply and be safe from an accidental short-circuit.

If you have an aftermarket horn where you can access the contacts freely, even better. You can connect the power input directly to the contacts (without wire extensions) and test the horn.

  • Connect the power supply

On most power supplies, the red clamp will be plus (+) and the black will be minus (-).

On a car horn, you can’t make a mistake in mixing up the plus and minus. But nevertheless, if there are markings on the horn, connect the red clamp to plus (+) and the black one to minus (-).

Once you’ve connected it, the horn will immediately make a sound or not and you’ll know if the car horn is faulty.

A tell-tale sign of a  faulty car horn is if there is no spark when touching the horn contacts.

If there’s a small spark but the horn doesn’t produce noise, then you can try to adjust it.

I myself prefer to use jumper cables and the car battery (straight from the car) as a power supply.

Just connect the jumper cables directly to the horn contacts or wire extensions you’ve previously made.

Quickest way and with least fuss; just take care not to make a short-circuit while testing the horn.

how-to-jump-start-featured-image


 

HOW TO ADJUST A CAR HORN?

Most people aren’t aware of the fact that car horns are meant to be adjusted.

This means you maybe don’t have to buy another horn so try this out before purchasing a new one.

Almost every car horn has an adjustment screw on the back of the horn. The screw serves to adjust the distance of the membrane inside the horn thus changing the sound.

Also, this procedure is good for when filth gets inside the horn. The membrane can get stuck so turning the adjustment screw loosens it and enables the horn to produce sound again.

The adjusting screw is usually covered with plastic or rubber resin making it hard to spot (which is perhaps why people don’t know about the adjustment part).

Here’s the procedure once you’ve taken off the car horn:

  • Find the adjusting screw

car-horn-adjustement-screw

 

It will look like a small bulge on the back side of the horn,usually on the opposite side of the connector. You’ll easily recognize it by the plastic or rubber resin covering it.

  • Remove the plastic or rubber resin that’s covering the screw

You can use a screwdriver, scalpel or knife to pick the resin out. It’s pretty tough to get out, so have some patience. You’’ll see a screw head emerging. Try picking out as much as possible so you can properly insert the screw driver.

  • Connect power output to the car horn

how-to-jump-start-featured-image

  • Start turning the adjustment screw left or right. If the horn membrane is stuck, then you should turn the screw from full left to full right at least once.

adjustment-screw-direction

  • If the problem is adjustment, a sound should appear once you’ve turned the screw.
  • Rotate the screw in any direction where the sound gets better and clearer.

Besides fixing the car horn, you can use this procedure to adjust the present horn sound (if you don’t like it).


 

HOW MUCH DOES IT COST TO REPAIR A CAR HORN?

car-horn-replacement-cost

Car horn repair is one of the cheaper ones on the car. Only exception is if the indicator stalk has malfunctioned. This will set you back a hefty sum. But these types of malfunctions are really rare.

Besides the indicator stalk,most expense comes from the horn itself. The lower stated estimate varies depending on the car model and your market.

New car horns average from about 10,00 to 20,00 Euros a piece, depending on the quality and brand.

Replacement car horns (same as from the manufacturer) are most popular as they already have predefined connections and brackets making the replacement much easier. Only difference from the original may be the sound they produce.

Different or custom aftermarket horns start from about 10,00 Euros and the price usually depends on the quality and brand name.

If you want a different and perhaps more louder sound or different sound levels, then prepare anything from 20,00 Euros to about 80,00 Euros.

If you want to go overboard, then you can spend over a 100,00 Euros on air-compressed ones.

Aftermarket horns, especially if they’re more powerful, usually need extra relays (even if one is already installed on the car).If you don’t take care of this, you may cause damage to the wiring installation, indicator stalk or else due to overload.

Additional brackets may also be needed if there is more than one horn in the set.

Then there’s the option of buying a used one. The price is usually about 5,00 Euros or if you have an acquaintance at the local junkyard, you’ll probably get it for free. This is not a bad option, just test the horn before you buy it.

If someones going to do the repair for you, prices for labor shouldn’t be high, especially if only the car horn needs replacement and everything else is OK.

The replacement itself (if the conditions are normal) shouldn’t cost more than 10,00 Euros (at least in my country) and in some shops the replacement is free if you buy the horn from them.

Exceptions are car models that have poor access to the car horn. This means more work around dismantling plastic covers in order to reach it. This will be more expensive for sure. Besides that, extra mounting of brackets, relays and additional wiring will certainly cost more.

A DIY job means you’ll only have the cost of a new car horn. Other parts like relays, fuses, connectors are mostly cheap to buy (a couple of Euros).

Possible difficulties in a DIY option could come from mounting custom aftermarket horns which need different brackets and additional relays or wiring. Here you have to be a bit careful especially around wiring.

If you have a problem with the indicator stalk, I wouldn’t recommend to do it as a DIY job without some serious experience around the car.

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