The cooling fan turns on on a cold engine: the main reasons and solution to the problem

As you know, various malfunctions of the engine cooling system do not allow the engine to reach the optimal temperature regime. The engine may overheat, which can lead to rapid breakdown, or remain cold, that is, not reach operating temperature.

Modern cars use a combined internal combustion engine cooling system: liquid and air cooling. By liquid we mean the circulation of antifreeze or antifreeze through special channels in the cylinder block and cylinder head of the engine.

The coolant circulates thanks to a pump. For additional cooling, the coolant can also circulate in a small circle (inside the engine) and in a large circle, that is, through the radiator.

Air cooling is implemented using a fan, which removes excess heat by supplying an air flow into the engine compartment to blow over the engine. The specified fan is activated when the heating of the unit is sufficiently high.

However, quite often drivers are faced with the question of why the cooling fan turns on on a cold engine, the engine fan turns on in winter or spins constantly. In this article we will talk about the reasons why the cooling fan operates on a cold engine, the engine cooling fan does not turn off, or the specified fan does not work correctly.

How everything works

The boiling point of antifreeze fluctuates around 130-140 degrees Celsius. Whereas normal engine operation is accompanied by a temperature of 85-100 degrees. At this indicator, the coolant circulates, taking some of the heat from the engine. Thus, preventing it from increasing the temperature.

With the help of a pump, the liquid passes through the system, moving to the radiator to cool. Then the circle repeats. If you turn off the engine, the fluid will stop moving and cooling, as a result of which its temperature will increase

.

But it is worth saying that the engine is capable of heating antifreeze only during its operation. That is, the liquid cannot heat up from the motor more than it is after it is turned off. Temperature readings will drop as the engine cools. This means you shouldn’t be afraid to turn off the engine.

with the radiator fan running.

If the liquid boils after turning off the engine

, which means it
was already overheated
. Therefore, it is worth checking for problems such as: lack of antifreeze, damage to the cooling system or improper fluid circulation (large and small circle).

avtoexperts.ru

When the engine is running, the temperature in the combustion chambers reaches about 1500-2000 degrees Celsius. If you do not remove heat from the cylinder walls, then overheating of the engine is inevitable and, as a result, expensive repairs or replacements.

Cooling Fan

To maintain the operating thermal conditions of the engine (+90 degrees) in any operating conditions, a cooling system is provided. It includes the following elements:

• Radiator; • Expansion tank; • Pump; • Thermostat; • Fan; • Temperature and fan sensors; • Set of connecting pipes; • Heater radiator; • Antifreeze.

Diagnostics

Before trying to determine why cooling system fans may turn on when the engine is cold in cars, it is recommended that you understand the operation of this unit.

The fan is turned on due to the operation of a special sensor, which activates the rotation of the blades. This controller is located at the bottom of the cooling radiator.

There are some modern cars where the engine control unit is responsible for starting, although this is rather a rarity and the exception and the rule.

When the cooling liquid (coolant) reaches the required temperature, which is usually in the range of 100-105 degrees Celsius, the sensor closes the electrical circuit, and this allows the fan to turn on. It starts blowing on the radiator. This achieves a better cooling effect, since the air and liquid systems are combined.

At the same time, there are situations when the engine is still absolutely cold, it does not require any additional cooling, but the fan still turns on. This is not a normal condition. It is necessary to look for the reason for this behavior of the cooling system and eliminate any malfunctions that have arisen.

If you continue to ignore the constantly running fan, the initially simple discomfort will give way to more serious problems.

But here it is important to note that the constant operation of the blades is not as dangerous as a complete failure of the device. Although this fact is absolutely not a reason to do nothing

It all starts with diagnosis. The simplest and most convenient in this regard are injection engines. To detect a malfunction, it is enough to conduct computer diagnostics. This is done both in a car service center and in the garage with your own hands.

Connecting to an electronic control unit makes it possible to obtain error codes that are not difficult to decipher and understand the true reasons for this behavior of the cooling system fan.

There are situations when the ECU detects a malfunction in the cooling system and causes the fan to spin constantly, even when the engine is cold. This is a kind of protective function aimed at preventing possible overheating of the internal combustion engine. Therefore, when errors are detected and after troubleshooting, a reset is required. To erase errors, you should look at the owner's manual for your car. On some cars, it is enough to remove the terminal from the battery, and the errors will be erased. On other cars, errors are erased using connected diagnostic equipment.

If the option of computer diagnostics does not suit you or it cannot be used for one reason or another, you will have to use the method of elimination to check all potential sources of trouble.

Content

• Sensor short circuit
• Insufficient fluid
• Weight
• Thermostat

There may be several reasons for this behavior. It is advisable to find the breakdown, because a constantly running fan is not only a discomfort, it may be a harbinger of more serious malfunctions. Although it should be noted that a constantly running fan is less dangerous than its complete failure.

Diagnostics

.
On injection cars, checking and finding the cause can be much easier. It is enough to carry out computer diagnostics. Typically, error codes quite accurately indicate the cause of the failure. On some models, if there is a “cooling system malfunction” error, the fan will spin constantly. This is protection against overheating. Even after eliminating the problem, it will not stop on its own. Errors need to be cleared. To do this, simply remove the terminal from the battery for a few seconds. Errors that have already been eliminated will be erased, and everything will return to normal.

Auto-assistance

On the VAZ-2110, in the engine cooling system, there is an electric fan, which turns on when the coolant temperature reaches 100-105 degrees Celsius. It is to this temperature that the fan switching sensor, which is located on injection engines in the outlet pipe of the cylinder head, is configured. Its factory marking is LS0112. In addition, the electrical circuit for turning on the fan includes fuse F7, located in the mounting block and a fan relay located in the car interior behind the right panel of the front console.

Therefore, if malfunctions occur that lead to the engine cooling system fan not turning on, you will have to look for this reason precisely in those nodes that were reported just above. Although there is one more point not related to the electrical circuit for turning on the fan.

The fact is that at a temperature of 100 degrees, water, which is an integral part of antifreeze, boils at normal atmospheric pressure. If the safety valve located in the cap of the expansion tank is faulty and there is atmospheric pressure in it, and the fan switching sensor has an operating temperature of more than 100 degrees, then the coolant will boil and the fan will not turn on, although the entire electrical circuit for turning it on is completely working. We change the cap of the expansion tank to one that will maintain the pressure in the engine cooling system above atmospheric pressure, then, according to the laws of physics, the boiling point of water will rise above 105 degrees, which means that the fan will have time to work.

When troubleshooting an electrical circuit, you need to start by checking fuse F7, for which you will have to open the mounting block. If it is intact and its contacts are not oxidized, then our further path lies to the fan switch sensor. You can check its performance yourself, without computer diagnostics, as follows.

The first thing to do is to warm up the engine to a temperature exceeding one hundred degrees, and then turn it off and turn on the ignition again. Open the hood of the car and remove the terminal from the fan switch sensor. If after this action the fan of the engine cooling system starts to rotate, this will indicate that it is working, but the sensor needs to be replaced. If the fan does not work, then this will indicate a malfunction, and the switch on sensor in this case will be operational.

To troubleshoot the fan motor, it will have to be removed from the vehicle. Possible causes of the malfunction may be: wear of the commutator brushes or their freezing and short circuit in the armature winding, but in this case a characteristic smell coming from the electric motor will be felt.

If under the hood of a VAZ2110 car all fan switching units are working properly, then you need to check its switching relay. To do this, remove the trim on the right side of the front console by unscrewing two screws. There you will see three standing relays. Typically, the fan switch relay is located in this row, the outermost one, towards the front of the car body. But, in order to make sure that it is located in this place, it is necessary to examine the bundle of wires suitable for it. The colors can be seen on the electrical diagram of the VAZ-2110. The test is carried out by replacing the fan relay with a known good one.

Provided that the driver was unable to independently find the cause of the malfunction in the operation of this system, then in this case, he will have to contact a service station to conduct computer diagnostics of the electrical circuit for turning on the fan.

Location of the coolant temperature sensor and its replacement

Replacing the fluid temperature sensor is not a difficult task (although a lot depends on how the engine is installed in the chamber). Most often it is located in the engine head and should be looked for in its vicinity. When checking its condition, it is necessary to take into account the fact that the car may have a second, so-called Liquid Temperature Sensor located on the radiator itself.

Location of the coolant temperature sensor and its replacement

This was the case with the presented Aveo T300. However, the faulty sensor was located in the engine head and was very easy to access . This can be achieved manually without removing the motor housing. Although the Aveo T300 is more than the latest Opel Corsa design, it is still a car with good access to engine hardware. The second of the sensors, the so-called Controlled one, fortunately, was in good shape, but even the Aveo T300 has pretty good access to it.

When replacing the coolant temperature sensor, the coolant must be drained from the system, since the sensor is partially immersed in it. After replacing the sensor, fill the system with new coolant, drain it and warm up the engine.

Closes the sensor

In frequent cases, the fan operates immediately after the ignitor is turned on. This occurs during the process of closing the sensor contact. In this way, it is possible to ensure the constant operation of the blowing object. This method is considered the most harmless in the process of observing breakdowns. If the ignition is in the on mode, this will lead to battery discharge.

To carry out a thorough check, it is necessary to install a cold sensor and measure the resistance at the terminals. If the sensor is working properly, then the resistance indicator will show the process progressing to infinity. With less resistance, the contacts close.

Accordingly, to ensure performance, you will need to change the product. A thorough diagnosis will immediately indicate the presence of breakdowns using a special code. That is, when the sensor turns on, it is possible to determine the indicator.

Thermostat problem

Every modern car is equipped with a thermostat with a sensor. This invention promotes efficient control of a cooling system. However, there are certain disadvantages here. If a malfunction is observed in the thermostat, the fan will function without fail.

The device can be checked using special equipment. When the unit is cold, the resistance should show infinity.

Now, you know why problems occur in the engine and how to properly diagnose it to ensure that the device operates in the correct mode.

Source

Insufficient fluid

Very often the sensor reacts to a small amount of liquid in the system. At the same time, the existing antifreeze heats up extremely quickly. This starts the fan. The most common cause of such a malfunction is a simple oversight. Drivers often forget to control the amount of coolant. It gradually evaporates, and as a result the radiator is half empty.

A small amount of liquid heats up very quickly, and the temperature of the liquid does not coincide with that of the engine. It turns out that the engine has just been started, it has not yet warmed up, but the cooling fan is already threshing, since the liquid has already heated up. The problem can be solved quite simply, you need to add antifreeze and bleed the cooling system to rid it of air pockets.

The fan may also short to ground. This happens for various reasons, but most often due to poor screwing of the corresponding wire to the body. In this case, the fan is connected to the battery directly. And he starts working non-stop. The main problem here is the possibility of the car catching fire if there is a stronger short circuit with greater heating of the wires.

To resolve, check all connections related to the sensor. All wires must have intact insulation. They must also be securely fastened to each other. Any small gap can lead to a problem.

Many modern cars are equipped with thermostats with sensors. This allows you to more efficiently manage the cooling system. But such management has its drawbacks. In particular, when the system breaks down, various “miracles” can begin. If the sensor installed on the thermostat fails, the fan will run constantly. The reason for this is the following. The control unit, not receiving signals about the operation of the thermostat, goes into emergency mode. At the same time, just in case, the fan turns on; in case of such an error, it will work constantly.

Checking the sensor is quite simple. Like any temperature sensor, in normal condition, it should show infinite resistance when the engine is cold, in all other cases it should show from 100 to 500 ohms. If the check shows different readings, it is better to replace the sensor. Fortunately, it is quite inexpensive.

Air temperature sensor

. Some modern cars are equipped with additional oncoming flow temperature sensors. That is, they react to the ambient temperature. If the indicator specified in them is exceeded, they give a command to turn on the fan. This is done to increase the cooling efficiency of the motor.

This scheme is often found on foreign cars that have sandwich radiators consisting of 3 layers. In this case, the fan will work almost all summer even on a cold motor. It is not recommended to disconnect the sensor; this may lead to engine overheating.

Contacts

. On cars with fan control via an ECU, problems with contacts may occur. They oxidize and stop transmitting signals to the control unit. It, in turn, goes into emergency operation mode, which is expressed by turning on the fan, as well as changing the operating mode of other systems. In general, it is advisable to clean contacts twice a year in spring and autumn. But, if your fan suddenly starts spinning from the moment you turn on the ignition, clean the contacts and coat them with a special lubricant.

Air conditioner

. On some models, the air conditioner has much in common with the cooling system. Therefore, a clogged air conditioner radiator causes the fan to spin. This can be treated by flushing the radiator. Ideally, it is better to flush both radiators at once. This will make the operation of this paired system as efficient as possible.

Conclusion

. For many drivers, the principle of operation of the cooling system is a dark forest. People start thinking about how and what works there only when there are signs of a malfunction. That’s when people start wondering why the cooling fan turns on when the engine is cold. This is very scary for many inexperienced drivers. In fact, this is not a very terrible breakdown, but for your own peace of mind, it is better to check the cooling system and fix the breakdown.

Diagnosis and common causes of cooling system problems

Of course, any on-board computer error related to the cooling system will not be eliminated; after eliminating the malfunction, reset the errors from the on-board computer by disconnecting the power terminals from the battery for about 10-15 seconds.

Closing contacts

One of the most common causes of this breakdown is a banal short circuit of the contacts of the coolant temperature sensor. In this case, when the ignition is turned on, the cooling fan turns on, since electric current is constantly supplied to the fan due to a short circuit. The consequence of such a malfunction may be, perhaps, accelerated discharge of the car battery.

We recommend reading an article on the topic: how to extend the life of a car battery. This article talks about the reasons for the short life of the battery, how to actually extend it, as well as the main signs of battery failure.

To diagnose this malfunction, you should disconnect the sensor and use an ohmmeter to measure the resistance at its contacts. If the sensor is working normally, then the resistance will be extremely high (the readings are only nines, which is analogous to “infinite” resistance). If the resistance is low, then the contacts are closed and the sensor must be replaced.

Also similar symptoms include a short circuit of the fan terminals to ground, in which case it will also work constantly as soon as the ignition is turned on. Since the voltage is supplied directly from the battery.

Small amount of antifreeze

Thermostat and its sensors

On some modern cars, the cooling system is equipped with thermostats with sensors that regulate the operation of the cooling system more efficiently. However, this design is more complex in structure than a conventional one, and due to its complexity it is susceptible to various problems. If the operation of a specific sensor that is connected to the thermostat is disrupted. Or the cooling control system does not receive data from the thermostat sensors, then, as a rule, it “goes into protection”, turning on the fan for constant operation. Checking these sensors is, in principle, similar to checking the contacts of a conventional DTOZH. We measure the resistance, and if it is low, then the sensor should be changed.

Oxidation of contacts

It is worth noting that the ECU can also “go into defense” in cases where the fan is controlled through the on-board computer itself. The reason for this may be problems with contacts. As a rule, contacts tend to oxidize over time, which greatly complicates the transmission of signals from sensors to the ECU. And if the required signal does not pass through at all, then in this case the control unit forcibly turns on the cooling fan, regardless of the engine temperature.

To eliminate it, you just need to clean the contacts and coat them with insulating grease to prevent the spread of corrosion. By the way, this procedure is recommended to be carried out 2 times a year to avoid unpleasant situations at the most inopportune moment.

Let's watch the video, the reason for the periodic switching on of the fan on a cold engine (Mazda 6 car):

Problems with the air conditioning system

On some vehicles, the air conditioning radiator is directly connected to the engine cooling system. And when the radiator of the air conditioning system becomes clogged, the operation of two systems at once is disrupted. Although the fan does not turn on immediately in this case, this problem can lead to much more serious consequences, including engine overheating.

To fix it, you need to clean the radiator, or preferably two at once. For more productive operation of these two interconnected systems.

That's all we wanted to say on this issue. In fact, this is not the worst malfunction, but if ignored for a long time, it is fraught with certain consequences. Therefore, you shouldn’t delay repairs either, and if the engine cooling fan turns on when you turn on the ignition, it is recommended to carefully check the cooling system for problems and fix the breakdown as soon as possible.

Source

Main types of radiator cooling fans

Today there are only two types of fans:

• Mechanical;
• electronic.

Mechanical (works when the crankshaft rotates). To maintain the integrity of the device and blades at high speeds, the fan impeller is connected to the pulley via a hydromechanical drive.

When the crankshaft rotation speed increases, the clutch performs light braking to prevent damage to the device. Although earlier the first models of vases did not have such a device.

Electronic. With the development of technology, electronic drives began to be in demand. It consists of two main components - a control system and an electric motor. The use of electronics made it possible to ensure uniform cooling of the power unit and eliminate the risk of damage to the fan.

RESULTS

The fan is an important device for ensuring normal operation of the motor. It helps the structure to cool effectively even at maximum engine speeds

Devices with electronic control units are becoming increasingly popular.

Materials: https://www.autonastroy.ru/pochemu-vklyuchaetsya-ventilyator-ohlazhdeniya-na-holodnom-dvigatele/

Design and principle of operation of the fan

Before you move on to repairing the fan, you should understand the principle of its installation on the cooling system. To do this, it is better to use the following simple diagram, on which the following main parts are indicated by numbers:

1. — cooling radiator.
2. - cork.
3. - electric fan motor.
4. - protective casing.
5. - fan impeller.
6. — damper pillows.
7. - coolant drain plug.

In addition, a diagram of the electrical equipment of the cooling system, which looks like this, will also be very helpful in repairs:

As you can see, the start of the cooling fan is controlled by a relay, which starts after receiving a signal from the temperature sensor.

Once the liquid in the radiator reaches a certain temperature, the temperature sensor closes and thus triggers the fan to start.

Once the temperature of the liquid in the radiator drops below a certain point, the sensor will open and the fan will automatically turn off. But, as already mentioned, sometimes this does not always happen.

Checking and replacing the Kalina cooling fan resistor

Removing the additional fan resistor is done as follows:

• put the car on the “handbrake”;
• open the hood;
• remove the ground wire from the battery;
• remove the engine splash guard;
• unscrew and remove the engine crankcase protection (if installed);
• press the block latch and unplug the electric fan power supply wiring harness;
• Using a Phillips screwdriver, unscrew the two screws holding the additional resistor;
• move aside the resistor mounting bracket together with the block;
• pull out the resistor.

Checking the resistor consists of two stages:

• visual inspection of the integrity of the spiral;
• checking the resistor winding for open circuit using an ohmmeter.

If a winding malfunction is detected, the resistor must be replaced with a new one. If the thermal fuse is faulty, then all you can do is replace it. To do this, you will need a soldering iron to remove the burnt fuse and solder a new one in its place. All that remains is to put the parts in their original places. Installation of the Kalina cooling fan resistor is carried out strictly in the reverse order of removal.

Without maintaining normal temperature conditions, it is impossible to imagine the operation of an internal combustion engine, which is why automakers pay special attention to ODS. The Lada Kalina uses liquid cooling

It is more complex than air and consists of more elements. One of them is the cooling system fan. If it does not work or does not work correctly, it will not be possible to effectively cool the engine.

water pump

In many cases, the reason for the increase in coolant temperature in the radiator is poor operation of the water pump. In this case, the antifreeze moves slowly through the system and heats up too much. Once it gets into the radiator, it does not have time to cool down to normal temperature, and goes around the next circle, heating up even more. If the pump at least works, then this problem is expressed only by the constant operation of the fan. If the pump fails completely, then the car will “boil” in a matter of minutes. This is an extremely dangerous condition that almost always leaves consequences in the form of engine problems.

Usually the water pump does not suddenly fail. First, it gives signals about its malfunction. The first warning sign is an increase in the frequency of operation of the radiator fan. The main cause of failure is destruction and jamming of the bearing. Therefore, a manifestation of a breakdown may be a howling noise from under the hood or a knocking sound that is clearly audible when idling. Often a knocking sound from the pump is mistaken for a camshaft fault. The breakdown is eliminated by replacing the pump; in some models it is possible to replace only the front part of the pump along with the bearing.

Cost of replacing the coolant temperature sensor

The coolant temperature sensor is a relatively cheap component, although much depends on the popularity of the car model. In the case of the Chevrolet Aveo T300, the original part costs about 1,200 rubles. A replacement RIDEX can be purchased for about 400 rubles, and for ABS - 700 rubles.

To replace the sensor, an authorized service center charges a fee of approximately PLN 160. In an unauthorized workshop, the cost of the same service will be about 1,700 rubles. The difference is therefore clear, especially when you consider the relatively small amount of work required to complete the job.

Possible causes, their search and solution

There may be several reasons why the cooling fan turns on on a cold VAZ 2114 engine.

The most likely of them are:

• low level of coolant in the system;
• sensor failure;
• fan short circuit;
• thermostat failure.

You should start your search with the first reason, since it is the most probable and at the same time the most quickly resolved. When the coolant level is low, the sensor can operate almost immediately after starting the engine, thus turning on the fan. This is due to the fact that a small amount of liquid heats up very quickly, while the engine itself is still “cold”. In order to solve this problem, you just need to add coolant to the required level.

If it turns out that there is enough antifreeze in the system, and this is not the reason, then you should check the sensor itself. It happens that it “sticks” in the closed position, as a result of which the fan circuit is always on. You can check the functionality of the device using a multimeter.

If you measure the resistance at the sensor contacts with the engine off, the tester should go off scale or show 0, depending on the model of the device (that is, the resistance will tend to infinity). If the multimeter shows very specific numbers, then the sensor is permanently closed, and it should be replaced with a new, similar one.

If the sensor also turns out to be working, then you should check the fan. Sometimes (especially if the housing is poorly screwed on or the wires are poorly insulated), it shorts to ground, as a result of which the fan starts working directly from the battery, without the participation of an electronic circuit with a sensor. This cause can be eliminated by checking and tightening all fasteners, as well as insulating exposed wire sections.

It should be remembered that such a malfunction is quite serious and can cause:

1. Rapid fan wear.
2. Battery discharge (if you leave the ignition on without the engine running).
3. Car fires (due to strong heating of wires).

That is why special attention should be paid to searching for possible faults (exposed sections of wires). The last reason that can lead to the fan turning on spontaneously is a breakdown of the thermostat (or rather the control sensor installed on it)

The bottom line is this: if the thermostat sensor fails, the electronic unit automatically starts a fan to cool the system, since the electronic unit cannot accurately control the temperature of the liquid. A kind of “reinsurance” is performed in case of possible overheating

The last reason that can lead to spontaneous turning on of the fan is a breakdown of the thermostat (or rather the control sensor installed on it). The bottom line is this: if the thermostat sensor fails, the electronic unit automatically starts a fan to cool the system, since the electronic unit cannot accurately control the temperature of the liquid. A kind of “reinsurance” is performed in case of possible overheating.

In order to identify a sensor failure, you will again need a multimeter. When checking, you should measure the resistance between the sensor contacts (with the engine off, of course). Normally, it should be no less than 100 and no more than 500 Ohms. If the values ​​obtained during measurement are outside the limits of this norm, then the sensor should be replaced with a new one. Finishing the conversation about the possible reasons for the fan turning on spontaneously, we should say a few words about how to prevent them.

To do this you will need:

• promptly monitor the coolant level in the system;
• periodically check the condition of the electronic wires of the cooling system;
• clean the sensor contacts from emerging oxides (it is recommended to carry out a similar procedure twice a year - in autumn and spring).

If you notice that the fan begins to turn on on its own, then the search for a breakdown cannot be put off until later, since the consequences (in some cases) can be extremely serious.

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Good afternoon. I have this problem. After starting the engine, about ten minutes later the radiator fan starts working. But the coolant temperature is about 70. At the same time, the check light comes on. The revs start to fluctuate and eventually the engine stalls. When restarted, the engine either starts with difficulty or does not start at all. But the fan works periodically whether the engine starts or not.

Source

The fan comes on when the engine starts on the Priora

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There are several options here.

(If you are absolutely sure that the Temperature Sensor and relay you replaced are working.)

An error was once entered into the controller, which it no longer displays, but simply turns on Carlson. But as far as I remember, usually the Carlson does not turn off and keeps pounding even for some time after the ignition is turned off.

In general, it still looks like a low-quality, sticky relay.

ALL errors on the controller are erased by disconnecting the battery. but that's not the point. I went to the diagnostics, there was only one error (invalid value of the temp sensor), but after replacing it with a new one, the situation continues. I changed the relay myself, although I’m not 100% sure that I changed the right thing.. there were three of them.. on the market they said the one opposite the fan fuse

In the description of any sensor error, there is a continuation, read in the injection primer: like “The sensor or its circuit is faulty”

So, in your case, most likely the chain, i.e. either the wires, and the wires to the DTOZH are always taut, or the wires are sealed in the connector. And a break in the DTOZh circuit, with the ignition on, will definitely cause the fan to turn on. Turn on the ignition and move it, swing the wires to the sensor.

The wires to the sensor were moving, nothing was wrong... the contacts were good, and I changed the relay correctly. k7. What other wires can be moved and where?

Not a single relay in the switching unit is responsible for injection. The fan relay is one of three under the center console next to the ECU, the fuse is there. And you can move at least the entire injection harness. There have been miracles with wires breaking in the harness itself. Once even in the passage through the motor wall. But usually at the connectors of both the sensor and the ECU.

Yes, there was one ten with the spontaneous inclusion of Carlson. I fucked with her for two evenings. Only the scanner helped. It turned out that there was a short in the harness along the command circuit for requesting to turn on the air conditioner (which was not there, but there was wiring to it in the harness), and a request to turn on the air conditioner causes the radiator fan to turn on. Since the owner of the car had no plans to install an air conditioner, he simply cut off the air conditioning request wires right at the ECU connector.

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Confinement of mass

The functioning of the fan depends on different methods, as you have already seen from reading this article. There is another reason that disables the fan's performance. For example, if the corresponding wires are poorly screwed to the body, the fan is connected directly to the battery. It should be noted that in this case, it is necessary to take timely measures to avoid serious problems.

With this option, you can expect the car to catch fire. If a strong short circuit occurs, then all the wires will heat up accordingly. To avoid serious consequences, you should check the connections and wires that have access to the sensor. Reliable fastening of wires and intact insulation reduces the risk of serious consequences.

What to do when turning on the cooling fan on a cold engine

Sometimes car owners are faced with a situation when the cooling system fan turns on and starts working when the engine is cold. Although, under normal operating conditions of this element, it must be activated only when the temperature of the internal combustion engine reaches certain values.

There are many reasons why this situation occurs on modern cars. Some of them can lead to serious negative consequences if measures are not taken in time to eliminate the causes and provoking factors.

To understand the situation, you need to find out the reasons for turning on the fan, understand its operation and find the best methods to solve the problem.

Common faults

Since the fan is spinning, it needs to be forced to stop and turn on only when there is a real need for it.

There are several main reasons why cooling system fans may turn on when the engine is cold. This is related to:

• switch on sensor;
• coolant;
• mass;
• thermostat;
• temperature sensor;
• contacts;
• air conditioning.

Each of the points may be the reason why the fan turns on and starts rotating when the engine is cold.

Power sensor

One of the most common reasons why a fan runs on a cold engine is a short circuit in the controller, that is, the sensor.

Quite often it happens that the fan starts when the ignition is turned on. If this occurs at the same time, the contacts on the controller have probably shorted. As a result, the airflow works constantly.

When is it advisable to repair it yourself and in the service?

If your car has problems with the electric fan of the cooling system, you can fix the problem in the sequence described above. Almost any repair can be done by yourself. Since the main problems come down to faulty sensors, replacing them will not be difficult. It is enough to dismantle the faulty part and install a new one in its place. If the problem lies in bad contacts, then they can be cleaned or, as a last resort, the connectors can be replaced. If you are not confident in your abilities, then in order to avoid new problems it is better to contact the service.

Video: solving the problem of a constantly running fan

To decide whether to carry out independent repairs in case of problems with the cooling fan or seek outside help, you can familiarize yourself with the approximate prices for a particular operation.

Table: cost of repairing the cooling system with your own hands and in the service

Constant rotation of the cooling fan on a cold engine is not normal. Therefore, you should deal with the malfunction that has arisen, find and eliminate the cause of its occurrence in order to prevent rapid wear of the device. Diagnostics consists of checking the coolant level, as well as the elements responsible for the operation of the electric fan, which every car owner can do.

Source

Lack of fluid in the unit

The sensor partially fails with the smallest amount of liquid. Even in the presence of antifreeze, the sensor immediately warms up. This process can disrupt the entire function of the system and cause many problems. Such a malfunction is characterized by a banal oversight.

With careful monitoring, you can get rid of serious problems and breakdowns. To do this, you need to check the amount of liquid. Since during evaporation there is no liquid in the radiator

If there is a small amount of liquid, the temperature reaches the unit temperature. For example, if you start the engine, it will not be completely heated, but the fan will immediately cool down. This process occurs due to the fact that the liquid heats up very quickly in the unit. Problems can be resolved in the simplest way. By adding a little antifreeze, you can avoid air locks in the system.

Cooling fan

Before we talk about troubleshooting, we should say a few words about the cooling fan itself. It serves to create a flow of air directed towards the radiator and serves to cool the latter. The fan turns on automatically when the temperature sensor located under the radiator is triggered.

When the coolant reaches a temperature of 100-105 C, the sensor closes and starts the rotation of the fan, which blows over the radiator and cools it. As you can see from this, normal fan activation is only possible when the engine is fully warmed up, and starting it when the engine is cold indicates obvious problems in the system.

Operation of the VAZ 2114 cooling system

Verdict

If there is enough antifreeze in the system, the reasons for the operation of the radiator cooling fan on a cold engine are exclusively electrical in nature. On the carburetor, this is a coolant temperature sensor built into the heat exchanger, or a closed ground.

On the injector, the most likely causes are a stuck relay, a shorted negative switch, and a DTOZH. On turbo versions, this is the control unit or the impeller itself. Emergency operating condition and bugs in the firmware are more serious reasons for the abnormal behavior of the wind blower.

The main reasons why the radiator cooling fan does not work

Let's look at the main options and places to look for faults:

1. Thermostat.

Thermostat removed from Lada Kalina

If it fails, this is the reason why the cooling fan does not work properly. To diagnose this malfunction, you should touch the lower pipe. If it is cold, then the thermostat is dead. Many Kalina car owners are accustomed to this phenomenon, since it often breaks down, and they carry a spare one with them. If it's not the thermostat, then the next step is the fuses. You need to make sure that they are working and all controllers too. The easiest way is to test them using a tester or ohmmeter. The fuse diagram is here.

Relay and fuse box

If the fuse is alive, then you will have to remove the additional fan control unit. To do this, it is worth moving the warm air duct and using a 10 mm wrench to unscrew the fastenings of the unit. Now you can get it freely. It has two relays that are responsible for turning on the fan and for high speeds. Let's diagnose both.

What to do if the lower radiator hose is cold

In most cases, the problem is related to the thermostat. This is potentially the most unreliable element of the system. You can measure the temperature of its pipes using a non-contact digital thermometer, and if the temperature difference exceeds the threshold for the valves to start opening, then the thermostat must be removed and checked, but most likely it will have to be replaced.

The pump impeller fails much less often. This only happens in cases of obvious manufacturing defects. Pumps are also not reliable, but their failure is manifested quite clearly in the form of bearing noise and fluid leakage through the seal. Therefore, they are replaced either prophylactically, based on mileage, or when these very noticeable signs occur.

Other reasons are more difficult to diagnose; it may be necessary to pressure test the system, check it with a scanner, measure the temperature at various points and other research techniques from the arsenal of professional motorists. And most often - taking an anamnesis; cars rarely break down on their own.

Perhaps the car was not looked after, the fluid was not changed, water was added instead of antifreeze, and repairs were entrusted to dubious specialists. The type of expansion tank, the color of the antifreeze in it and the smell will indicate a lot. For example. the presence of exhaust gases means a gasket breakdown.

If the fluid level in the expansion tank suddenly begins to drop, it is not enough to simply top it up. It is necessary to find out the reasons; driving with antifreeze leaking or leaking into the cylinders is strictly forbidden.

Messages 10

1 Topic by mastepanov2011 2017-03-04 23:02:53

• mastepanov2011
• Participant
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• Registration: 2015-04-14
• Messages: 137Thanks: 16
• Car: VAZ 2111 1.5 v8

Topic: Resolved: Fan comes on when ignition is turned on but does not turn off

Good evening guys, the problem is that when the ignition is turned on, the fan is triggered. I changed the relay to another one, it didn’t help, the fuse is intact, when you remove the chip from the dtozh, the carlson switches on. I think it’s the dtozh? I read articles, but I didn’t really understand. 2111 8th grade engineer.

2 Reply from krasnopolskaya.y 2017-03-04 23:10:38

• krasnopolskaya.y
• Experienced
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• From: Kletnya village
• Registration: 2016-02-29
• Messages: 276Thanks: 85
• Auto: 2112

Re: Resolved: When the ignition is turned on, the fan comes on, but does not turn off

open circuit of the sensor behind the thermostat

3 Reply from “Robotron” 2017-03-05 08:21:17

• "Robotron"
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• Registration: 2015-11-22
• Messages: 292Thanks: 81
• Car: VAZ - I turn it myself

Re: Resolved: When the ignition is turned on, the fan comes on, but does not turn off

The DTOZH itself is faulty or the circuit itself to the sensor, sometimes the chip itself is acting up to the sensor and it wouldn’t hurt to clean out all the masses. lada2111.rf/spravka/749-massa-2110.html

4 Reply from Patroclus 2017-03-05 14:01:31

• Patroclus
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• From: RUSSIA
• Registration: 2014-07-05
• Messages: 637Thanks: 104
• Car: Lada Priora 2171 Wagon: VESTA

Re: Resolved: When the ignition is turned on, the fan comes on, but does not turn off

wait, how does KARLOSON work when the chip is removed, IF IT ALREADY SPINS WHEN THE IGNITION IS TURNED ON??

5 Reply from mastepanov2011 2017-03-05 18:15:32

• mastepanov2011
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• Registration: 2015-04-14
• Messages: 137Thanks: 16
• Car: VAZ 2111 1.5 v8

Re: Resolved: When the ignition is turned on, the fan comes on, but does not turn off

I removed the ignition on chip, it turns right away, and when the chip on the sensor is in When the ignition is on, after 5 seconds it turns on.

Thanks, I'll take a look.

6 Reply from Patroclus 2017-03-06 00:18:29

• Patroclus
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• From: RUSSIA
• Registration: 2014-07-05
• Messages: 637Thanks: 104
• Car: Lada Priora 2171 Wagon: VESTA