The role of fuses in a car is very significant. They perform a protective function, protect expensive electrical devices from short circuit, from unexpected power surges. By saving any electrical appliance, the fuse sacrifices itself and stops functioning, blowing out. To restore the previous operation of a certain electrical device in a car, you just need to replace the corresponding fuse. But there are times when the fuse blows too often. In this regard, it makes sense to think about whether everything is in order with the automotive wiring? If you are interested in why this or that fuse blows in a car, then you will find the answer in this article.

The main causes of a blown fuse

Among the main reasons why the cigarette lighter fuse or some other consumer of electricity burns out, there may be both very serious and quite banal ones. For example, let's analyze a situation where the fuse of the dimensions blows. Just turn it on car light how it immediately goes out. And the reason can be completely ridiculous - the installed fuse has less power than is necessary for correct operation.

Let's say the passing current is 15 A, and the fuse is rated for 12 A. Of course, it will melt, since it is not designed for such a current. That's why it is necessary to install fuses only with the power that meets the requirements. In no case, as you already understood, do not install fuses with less power, and even more so with more.

In addition, if the fuse in your car blows constantly, then the fault may lie in the electrical circuit itself. Suppose the contacts on which the fuse sits are in bad condition. Soot appears on them, or the fuse has a poor fixation. As a result bad contact sparks occur, which contributes to the fuse blowing. And it doesn’t matter how high-quality and powerful the fuse you put in, it will still burn out until you get rid of the problem that has arisen, that is, you don’t clean the contacts.

Most serious problem This is, of course, a short circuit. For example, two wires with opposite polarities are in contact, as a result of which such a phenomenon occurs. AT this case Don't be surprised if you keep blowing a fuse. cabin heater, because until you replace the wires or isolate them, the situation will remain unchanged.

And of course, fuses can melt due to their Low quality. These are, unfortunately, not uncommon. Therefore, do not skimp and buy too cheap and unknown fuses.

Here we are with you and sorted out the most common problems of blown fuses. It is worth noting: if replacing the blown fuse with a new one and cleaning the contacts did not work, best solution will contact a qualified car service. With electricity, jokes are bad, because in such cases, your car is at great risk of fire.

Checking the functionality of the fuse

There are two ways by which you can check the performance of automotive fuses. The first is to extract them and visually diagnose, which is not entirely reliable. In this case, the use of a tester is implied. When checking the fuse with a tester, it must be set to check the continuity of the circuit. If the fuse is intact, the tester needle will tend to zero, which means zero resistance.

The second method for determining a blown fuse is a more convenient method than in the first case, and when using it, the fuse does not have to be removed from its socket. You will need a tester to test them. Turn on the idle circuit, and then, in turn, touch the probe to the fuse terminals. If there is voltage on one terminal and no voltage on the other, then the fuse is defective.

You must replace a defective fuse with a similar one that is rated for the same amount of current. Do not use "bugs" - they can damage the electrical equipment of the car. Even factory fuses can be defective and do not burn out during a short circuit, but simply melt.

To test them, you need to destroy one fuse. Wind it around the wire leads, and then touch the battery. A high-quality one will burn out immediately, and such a fuse can be safely used in a car.

To protect your car's new fuses during a short circuit, you need to find out the reason why it appeared. To do this, check the wiring for damaged insulation. Be especially careful when inspecting the places where the wires come into contact with the body. During the movement of the car, a repeated circuit will occur, so you need to understand, detect and eliminate its cause in a timely manner.

Replacing a blown fuse

Replacing a fuse in a car is actually not a difficult procedure, you just need to strictly adhere to a number of rules:

1. Find the correct fuse. This is perhaps the most difficult, given the lack of information about its location. Moreover, for a certain electrical system There may be multiple fuses.

2. Take it out. Sometimes this is quite problematic to do without special tools, for example, tongs. Due to the increase in the number of electronic modules in the car, the number of fuses is constantly growing, and there is no more space in it. Therefore, this problem is solved by reducing the size of the fuses themselves. This leads to the fact that it becomes almost impossible to easily get them, hook them and take them out with your fingers. But here, for example, in Ford vehicles fuse box lids have special tongs for removing fuses.

3. Make sure the fuse is blown. You can find out by looking at it. Often, fuses today are made of transparent plastic, through which a thin wire is visible, which in defective element melts, and it is clearly visible through the plastic.

4. Install the correct fuse in the correct location. The main thing is to install a similar fuse in the same socket where the failed “brother” was located. Fuses are available in different colors- blue, red, yellow, on which various numbers are written - 3, 5, 15, 20, 25, 30 and so on. This is the denomination. Never install a fuse of a different rating, this is important! If you removed the blue 30 amp fuse, then don't use 40 or 20 amps. This may result in expensive repairs. Set it exactly the same as it was. They took out the blue at 30, which means insert a new blue at 30! There is nothing difficult in this!

Second important task- place the removed fuse in the same place where you removed the old burned out one. It may sound funny, but in the dark, or with poor eyesight, people sometimes fall into the wrong nests, and the results of this are sometimes strange, but often deplorable. The point is that in modern cars fuses are in boxes with electronic modules. By putting the fuse in a different place, you can make the module work differently, and the car may start to behave strangely, for example, you will not be able to turn off the engine when the headlights are on, or when the ignition is turned on, the headlights, power windows or something else will not work for a couple of minutes. anything.

That's all. Enough simple rules which can be adopted and which can save you time and money. It is best to have complete fuses from those used in your car, a flashlight in order to replace the fuse in dark time days, tongs if you cannot remove the fuse with your fingers and perhaps a magnifying glass if you have poor eyesight and cannot see the fuse number and rating on it.

Many people ask me questions about the fuses in the car, namely, why are they needed at all, how do they work, why do they blow out? The questions are not difficult, but interesting, because we have not (in detail) climbed into the electrical wiring yet! And why not start with safety elements, of which there are several dozen in a car. I will try to you in simple words tell about them, as well as show, there will be photos and videos at the end ...

First, a little definition

Fuses or safety element is a component that is designed to protect electrical network or devices, vehicle components, from malfunctions, short circuits, high load, damage to the braid - in general, any overload that can disable the device.

In simple words, he himself “suffers”, but does not allow the rest of the equipment to be damaged, thereby often saving the car from a fire.

Fuse structure

This is a very simple element, which I want to emphasize is really compact, which simplifies their use in the car. It consists:

• From the case - usually it consists of plastic, rarely metal, or ceramics
• A contact group is two legs (or just contacts) that are connected to the car's network
• A working element is usually a thread, or a part of a metal plate, which, at a certain current strength, is destroyed, usually burns out or “evaporates”.

Previously, in a car, remember at least our “first” VAZs, cylindrical fuses were used with a metal strip, usually consisting of aluminum and a ceramic case.

On this moment a flat structure, two flat legs, a plastic body, and a thin working part (usually made of refractory wire) are used.

How does it work

In our case, we will talk about fuses specifically for cars, let me remind you that at the moment such elements exist in almost all electrical appliances, only they have a different voltage and current with which they work.

SO, the fuse is installed in the network, in the gap, that is, currents flow through it, it is a kind of switch. But it can only work with a current of a certain rating, what does this mean. Suppose it is designed for a maximum of 10 Amperes, if the currents go to 2 - 4 - 8 - 10 Amperes, everything will be fine, but as soon as the current is exceeded, for example - 12 Amperes and above, the thread that is built inside - burns out, thereby saving wiring and other devices from damage.

The guys put them on for a reason, but in order to protect them - corny wires so that they do not melt from high currents and do not destroy (and in worst cases burned), your car! They are needed, if you want, then this is a kind of fire alarm!

That's why manufacturers stick them in almost all the circuits of the car, because it's important!

Can it be removed?

Yes, of course you can, why not! After all, this element simply protects, if you go, a surge protector or UPS, it saves your computer, laptop or TV, monitor, from power surges or short circuits. If you plug the computer directly into the outlet, it will also work, only if the voltage is mixed up at the power plant, your equipment will burn.

Also here, if the fuse is excluded from the circuit, then when the rated voltage is exceeded, other elements of the circuit will heat up and burn out - wires, devices, etc. Often this leads to fires, because before the hot wire breaks, the winding on it lights up, it then sets fire to the inside of the car! And the car is on fire in minutes.

So guys, DO NOT REMOVE THE FUSES! This is a fact, they were not put in order for you to remove them.

We do not deal with nonsense, if it burned out, we change it.

Why are they burning?

Already answered from above, let's list the points to get fixed in my head:

• Short circuit
• Increasing the current strength in the network
• If you plugged in a device that is not designed for the network

That's actually all the reasons. The cigarette lighter fuse () often burns. Because we just don’t include anything in it - video recorders, radar detectors, navigators, kettles, heaters, etc. They went too far with something, and it all burned out, that is, it saved your network from damage.

Is it possible to put a larger fuse?

Many of us in the same cigarette lighter, trying to put the fuse more power. Do not do this - in no case !!!

After all, if you say, it is designed for 10 Amperes, and you put it on 16 Amperes, then your wiring will burn (melt) faster than the fuse itself!

Here less power- it is possible, but often it is not practical, it will constantly burn out, so you need to use the one that the doctor ordered.

Useful video

Actually, this is the end, I think it was informative, read our AUTOBLOG.

All circuits in the vehicle's electrical system are protected fuses, protecting electrical consumers from various kinds of overloads and short circuits. The exception is the chain, since it takes very high current, about 350 A.

The task of the fuse is to save expensive electrical equipment and save the car as a whole from a possible short circuit in order to avoid wiring fire and the car in general. In most cases, the fuse burns out from a short circuit in any consumer or wiring. The price of a fuse is disproportionately lower than any electric consumer, and in the event of its operation (burnout), it is simply replaced with a serviceable one from the spare parts kit.

Each fuse is designed for a certain current that it can withstand, depending on the number and power of protected consumers, and if the current exceeds the fuse rating, it will blow. Therefore, when a fuse blows, it is always necessary to replace a blown fuse with a fuse of the same rating.

It is allowed to temporarily install a fuse of a smaller amperage, with subsequent replacement with the required rating. For example, a blown 10A fuse can be replaced with an 8A one, it will simply work at a lower current value, but it will protect the circuit from overload and for the car it will be safe. If, however, a 16A fuse is installed instead of a burned-out 8A fuse, then a consumer located in the circuit designed for a maximum current of 8A can simply burn out during overload, since a 16A fuse can withstand a load of more than 8A.

Many, when a fuse blows, for lack of a spare, put various objects that have nothing to do with the concept of a fuse. These can be pieces of a nail, coins and other conductive objects that will remain intact even after complete combustion the entire circuit, since the same coin, for example, can withstand welding current.

The second thing that many motorists “sin” with is replacing a blown fuse without finding out the reason for its blown out -. For example, causes of generator failure, optics or signal that caused the fuse to blow. "It's good" if the installed new fuse immediately burns out again, which should already alert the car owner and force him to find the cause.

However, in most cases, changing fuse, drivers continue to move, since the installed fuse does not blow and it seems that everything is in order in the protected circuit.
But in most cases, (except for a power surge due to a failure in relay-regulator) something happened in the circuit and if you do not immediately find the cause, then there may be backfire.

Find a consumer, and find out the reason. why does the fuse blow which was re-installed uncomplicated and can be repaired do-it-yourself car without resorting to the help of a car service.

On the road, not everyone has a device for troubleshooting and you can determine it by performing simple steps, without a tester or control.

To do this, you just need to, guided by the description of the fuses, view all the circuits that it protects. Having learned what "sits" on this fuse, you need to start turning off consumers one at a time and without inserting a new one fuse(may burn out immediately) simply by shorting the fuse socket with a screwdriver for a moment.

If there is a problem, then when the sockets are bridged, a spark will jump. When, after disconnecting the next consumer, the sparking between the fuse sockets disappeared, then the problem is in the disconnected consumer, which needs to be repaired or replaced. Thus, you yourself determine the reason why does the fuse blow.

It is difficult to underestimate the role of fuses in the car, which are able to protect the electrical circuit of the car from failure in the event of a malfunction. Every driver saw the fuse box, many were faced with the need to replace these elements of the electrical circuit. But the situation in which the fuses regularly blow out cannot be considered normal, and you should figure out what is the reason for their failure.

Causes of blown car fuses

Each car fuse, located in the block and outside it, is responsible for the stability of a particular electrical circuit. If it burned out, then a malfunction has occurred, which may be single or develop into a trend. There are several main reasons that lead to the failure of fuses:

If one or more electrical appliances in the car stop working, the first thing to do is. Their failure leads to a break in the circuit, due to which the current stops flowing to the equipment, and it does not function.

Since the price of fuses is more than affordable, many motorists carry with them a whole set of such elements that can be installed in an electrical circuit if necessary. A blown fuse is a normal situation, since no electrical circuit is protected from current and voltage surges. However, when the fuse blows regularly, you should not only think about diagnosing the electrical components of the car, but also carry it out as quickly as possible.

If the fuse blows almost immediately after it is installed in the circuit, it is necessary to determine which device is causing the similar problems. For this:

After the faulty component of the electrical circuit is identified, it must be repaired or replaced.

Automotive fuses are hundreds of times cheaper than the equipment they protect. That is why it is not recommended to save money when buying fuses, giving preference to dubious models. It is necessary to buy only such circuit protection elements, the parameters of which are ideally observed.

Since it is not possible to check each specific fuse from an unknown manufacturer, when buying such elements of an electrical circuit, you should pay attention to the brands that produce them. Among the most famous companies manufacturers that produce quality fuses include Bosch, Hella, Vibe, Hollywood, CarPoint and SoundQuest.

When purchasing a lot of fuses from an unknown manufacturer, do not be too lazy to check them before installing them in a car. To do this, short-circuit a new fuse to the battery, and pay attention to its behavior. If it instantly blows, then the fuse is of high quality, and it will be able to break the circuit if a current flows through it that exceeds its parameters. In the event that, during a short circuit to the battery, the fuse does not blow out, but begins to melt, you should be wary of installing it in a car - it will not be able to instantly break the circuit, and destructive increased current will begin to flow to electrical appliances.

Half of the faults in the electrical equipment of cars are associated with fuses. Their number in the car can be more than a hundred.

The driver must know the types of automotive fuses, their purpose, methods for checking performance, methods for replacing and determining the rating.

Purpose

Automotive fuses (otherwise fuses) in electrical diagrams apply for:

• overload protection electrical circuits, ignition in case of short circuit;
• protection of the electronic components of the car in the event of a malfunction of electrical equipment and wiring;
• control of maximum currents in car circuits;
• a kind of diagnosis of a malfunction of the electrical equipment of the car.

The last function refers to the fact that if any electronic device blown fuse in the car serving this block, will be evidence of problems in the block.

Types and types of automotive fuses

Automotive fuses are classified according to the material of the fusible insert into:

• lead;
• tin;
• alloy (tin + lead);
• aluminum.

Them important characteristic is the response time. The faster the melting of the insert occurs, the more reliably the circuit will be protected in case of a short circuit for overheating of the conductors, possible ignition. To do this, inserts are made from metals and alloys with a lower melting point (transition from a solid to a liquid state of aggregation). In some types, a spring is used to accelerate the response (types FJ).

Fuses of various sizes are used in the car.

The following types of fuses have received the greatest application in car systems:

• MAXIFX- power fuses in engine compartment;
• FTX NORM - fuses in the engine compartment and cabin blocks;
• FNL VINI - in the engine compartment and saloon block fuses;
• FJ10 - in the underhood power fuse box.

Depending on the rating of the fuse, usually indicated on its body, an additional color coding, more precisely, the main color of its body.

Why do car fuses blow?

Consider why the fuses in the car burn - the most common typical causes.

1. Cigarette lighter

The cigarette lighter fuse often fails. In most cases, this is not related to smoking. Power connectors are often installed in the cigarette lighter additional equipment(radar detectors, navigators, other auto gadgets), compressor, charging device mobile equipment, splitters and tees of dubious quality.

In some cases, connecting several gadgets at the same time can lead to exceeding the maximum current through the power supply circuit of the cigarette lighter socket.

There are car owners who artificially increase the fuse rating in the power supply circuit of the cigarette lighter connector. Doing this is extremely dangerous! The cross section of the conductor leading to the connector may not be suitable for the increased current, it may overheat, causing a short circuit and fire.

Often such situations arise when using the advertised additional electric.

2. washer

The failure of this fuse is associated with the possible freezing of water in the tank and tubes of the washer system at negative and slightly positive temperatures. The mobility of the electric pump drive is disturbed, as a result of which the current increases, the fuse blows. To prevent such situations, it is necessary to timely replace the water with antifreeze liquid and purge the entire system of water.

3. Janitors

It breaks down if the wipers freeze to the glass, the gearbox is jammed. Therefore, before starting to move in the morning in the cold season, it is necessary to check the brushes for freezing to the glass.

4. Heated windows and mirrors

May burn out due to electrical short circuit. The most "weak" places of wiring are in the corrugated hoses of the front doors, the tailgate, under the driver's threshold.

5. Stoves

A 30 amp fuse is usually responsible for the stove. In case of wear of the electric motor of the stove, especially bearings and bushings, the current in the electric drive circuit increases significantly. To avoid such situations helps to timely conduct maintenance work oven fan.

6. Lighting systems

They often burn out if the power is set, non-standard lamps are installed, especially xenon ones with an ignition unit, the current consumption of which is much higher. With an increase in the nominal value, it is necessary to “strengthen” the electrical wiring of the lamps at the same time, laying wires of a larger cross section.

7. Engine cooling systems

They fail when the current consumption of the radiator electric fan increases for the following reasons:

• ingress of foreign objects into the area of ​​rotation of the fan blades;
• wear of fan motors;
• engine lubrication.

8. Engine control unit

Their burnout leads to failure to start the engine. For this reason, the driver must know where the fuses serving the engine control unit are located. Almost half of all malfunctions associated with failure to start engines are determined by their burnout.

9. Electric power steering

Power steering systems are increasingly being used in automobiles. The electric drive of the electric amplifier consumes a large current; at increased loads, the fuses often fail.

10. Electric parking brakes

Electric parking brakes for some car models (eg VW PASSAT B6) headache many car owners. electric drive parking brakes located in an "uncomfortable" place near the wheels.

This contributes to the mechanical destruction of the case, the ingress of moisture and dirt, as a result, jamming of the engine, blowing fuses in the power circuits.

11. ABS systems

As a result of pump wear, the current increases, the fuse blows ABS systems. This leads to inoperability anti-lock braking system brakes, especially needed in poor road conditions.

12. Central locking, power windows

Drives central lock, power windows often jam, causing fuses to blow. Also problematic is the short circuit of the wiring in the corrugated hose of the door wiring.

How to check the fuse for serviceability

Checking the health of the fuse must be done by dismantling it from the socket. An initial check can be made at the installation site, but in case of the slightest suspicion of a malfunction, be sure to pull it out.

Video - how to check the fuse in the car:

Before checking the fuse with a multimeter, it must be removed from the socket. The test itself is carried out in the position of measuring the resistance at the lowest limit, or the buzzer. The resistance of a good fuse should be zero.

You can also check it visually. The working element is usually visible through a special window, a transparent body or protrudes from the body. Such a check is often deceiving, since there are microcracks in the current-carrying zone that are not visible to the naked eye.

How to find its installation location in the car

In order to find the installation location of a particular fuse, you must refer to the vehicle manual. Not all manuals have information about fuse boxes. The most common places for their installation:

• in engine compartment from the driver's side;
• near the positive terminal of the battery;
• in the cabin under the dashboard;
• in the cabin in the glove box area;
• at the ends of the torpedo;
• under back seat(in some BMW models);
• in the trunk under the upholstery on the right or left side.

There are special resources on the Internet where you can find the location of these blocks and specifically the fuses that serve certain systems and devices of cars.

How to pull a fuse in a car

A car's fuse box usually contains a plastic tweezer that can be used for removal.

In some cars (for example, Honda), a special tool is used for dismantling.

Without special tool The fuse can also be removed manually.

Large fuses are removed with pliers. To dismantle some types of fuses (FJ12, FJ14, FJ15), you need to use a wrench or a screwdriver.

Video - replacing cigarette lighter fuses in Nissan Qashqai:

Calculation of its nominal value when installing additional equipment

When installing additional equipment, it is often necessary to change the fuse rating in the power circuit. For the calculation, it is necessary to have data on the power of the device or its resistance. For example, when connecting an additional light source in the form of a 60-watt lamp, you must use the formula:

• P - lamp power,
• U - voltage onboard network(12 Volts),
• I is the current in the circuit.

From the formula follows:

I \u003d P / U \u003d 60/12 \u003d 5 Amperes.

That is, when installing an additional lamp, it is necessary to increase the fuse rating in the circuit by approximately 5 Amperes, taking into account the current margin of 50%, you must select 7.5 Amperes. If two lamps are installed along the circuit, then the denomination is multiplied by 2, it turns out 15 amperes.

If the power of the device is unknown, its resistance is measured. The measurement should be made, since the Chinese ones have a large error, especially when measuring low resistances. For example, setting the notorious electric heater air in the cabin, measurements showed a resistance R equal to 0.4 ohms. The current is determined by Ohm's law.

I \u003d U / R \u003d 12 / 0.4 \u003d 30 Amps

If only a heater is connected to the cigarette lighter socket, the fuse rating should be at least 40 Amperes, taking into account the margin.

Video - choosing high-quality car fuses, checking them for integrity, calculating the value:

It should be borne in mind that usually when calculating the cross-sectional area of ​​\u200b\u200bthe conductor, it is taken as maximum current for 1 sq. mm of the conductor section, the maximum current is 4 Amperes. Thus, the cross-sectional area of ​​the wire going to the cigarette lighter socket must be greater than 30/4 = 7.5 sq. mm. The nearest standard section is 8 sq. mm. (for sure there is a wire with a cross section of no more than 6 sq. mm.) If during the operation of the heater you want to light a cigarette (using a double connector), the current may increase, and this is fraught with a blown fuse, even worse, ignition of the wiring.

Therefore, before increasing the fuse rating and installing additional consumers in the circuit, it is necessary to check the cross-sectional area of ​​\u200b\u200bthe wiring in the circuit, if necessary, install other wires.

If the accessory is powered by a fuse block, it is also necessary to increase the rating of the powerful fuse that serves this block. It is usually located under the hood or in the trunk if the battery is located there.

Common mistakes and their consequences

The main mistakes when installing and replacing automotive fuses in a circuit:

• It is impossible to increase the fuse rating without calculating the required cross-section of conductors in the circuit. If the wires cannot withstand large currents, they may overheat, resulting in a short circuit and fire.

• Replace the fuse with a good one of the same type. If you install another type, the contact areas of the fuse holder may overheat, which can also lead to a fire.

• In no case should you install a "bug". If the fuse has blown, then there are already problems in the circuit, possibly a short circuit. A bug will most likely lead to melting of the wiring. It is better to temporarily take a serviceable fuse of the same rating from a secondary circuit in the fuse box, for example, from a stove, heater rear window, fog lights, etc. Fuse kits can be purchased at your nearest gas station.

• Some motorists, with an increase in the frequency of blowing a certain fuse, increase (sometimes twice) its rating. This can lead to the failure of the block it serves. In such a situation, it is necessary to deal with the cause, not the effect.

If you use the car all the time, download and print the fuse diagram for your brand of car, keep this diagram in the glove compartment.