When the ignition is turned on, the fan is activated: both turn on

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

Another common problem is too little coolant. It is to its temperature that the DTOZH reacts. With a small amount of antifreeze, the liquid warms up much faster than the engine itself warms up, as a result the fan turns on too early. Add fluid to the required level and, just in case, check for leaks in the cooling system.

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 protection” 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.

The cooling fan does not turn on on the VAZ-2110: what to do

When planning to dismantle the cooling fan on a VAZ-2110, it is important to know the operating principle of the entire system. A variety of problems can cause a cooling fan to fail, such as:

• breakdown of the electric fan (starts only if the coolant temperature is maintained at 100 degrees);
• the fan switch sensor is broken (it works only in a certain temperature range, located at the base of the inlet pipe of the cylinder block);
• failure of the mounting block fuse;
• Malfunction of the cooling fan relay (located on the right panel of the front console of the vehicle).

When the expansion tank fuse fails, having internal atmospheric pressure, the internal liquid - antifreeze - will take on a boiling state, but the fan will still not be able to start, and in this case the problem will not be in the electrical circuit. The fact is that the VAZ-2110 has an injection type, which means that the fan will start only when the temperature is +100 °C. In this case, the expansion tank cap needs to be replaced. Provided that it is possible to maintain a pressure greater than atmospheric pressure inside, the boiling point will rise slightly, and this will allow the fan to start working.

If, however, the reason lies in a malfunction of the electrical circuit, then it is necessary to diagnose it. This is done as follows:

1. First, the functionality of the mounting block is checked, making sure that the contacts are in good condition with oxidation. If you are not satisfied with something externally, change the fuse or clean the contacts.
2. Now you need to examine the condition of the fan switch sensor. Start the vehicle engine and warm it up to 100 degrees. Next, turn off the car and start it again. Under the hood, remove the terminal from the fan sensor and see how the fan behaves. If it starts, the sensor must be replaced.
3. Then we move on to inspecting the electric motor. If all previous inspections of the parts have not yielded results, then there is nothing left to do but remove the electric motor and check the electric motor. There can be a huge number of problems with it: wear of the commutator brushes, their freezing, short-circuiting of the armature winding (in this case a pungent odor will emanate).
4. The last step is to check the functionality of the fan relay. If the whole problem is the fan start button not working, then you will need:

• remove the right console trim from inside the car, removing all fastening screws;
• find the relay we need (1 of 3);
• replace it with a new one.

In the case when the cooling fan on the VAZ-210 works constantly without turning off, both in hot and cold engine states, then troubleshooting can be different:

• if the contacts of the electric fan responsible for turning it on do not open, then the test is carried out using a multimeter, and if a breakdown is detected, the part is replaced with a new one;
• in the event that the temperature sensor or its circuit is broken, then it is diagnosed using an ohmmeter, and, in the event of a breakdown, a new sensor is installed;
• if the control unit of the injection system is broken, then the unit must be taken to specialists for inspection and its ECU or the entire unit must be flashed;
• if the thermal switch has open contacts, then the terminals that are the terminals of the thermal switch are disconnected and a new one is installed.

Even such a careful diagnosis of each part of the cooling system on the VAZ-2110 may not give any positive results, and the fan, as before, will not start working. Here you cannot do without consulting experienced specialists; you will have to take the car to a service center. There, the entire cooling system will be put through computer diagnostics to determine what is causing the cooling fan failure.

If your financial situation allows you to periodically visit auto repair shops, then by all means do so. No matter how you know your car, they will better analyze it and conduct a thorough diagnosis, allowing you to anticipate multiple breakdowns that could interfere with the implementation of your plans.

DVV

Sensors turn on

The fan switching sensor (FSW) occupies not the last place in the internal combustion engine cooling system. He is responsible for engaging the fans installed on the radiator and activated when the coolant temperature increases and standard cooling for the engine is clearly not enough.

If the DVV is connected directly to the ignition, and not to the relay, then it is recommended to carry out a different circuit by replacing the sensor. A sensor connected directly to the ignition may not work correctly. On some car models it is integrated with a relay, which looks noticeably more reliable.

The diagram looks like this in this case:

• The minus of the fan is connected directly from the battery, the plus - from the battery through a relay (it is also possible to connect the plus directly from the ignition);
• The sensor is also integrated with the relay on one side, and with the ground (any part of the car body) on the other.

Obviously, if the sensor is responsible for turning on the fan on the car, then untimely activation of the system may well be caused by damage to the element. Let's look at what the sensor consists of.

Both fans turn on when the ignition is turned on

Its device is simple. A bimetallic strip is installed at the bottom of the sensor. It is made so that when the coolant temperature increases, it deforms and thereby affects the contacts of the device.

Regarding the sensor connection circuit:

• Until the coolant heats up, the sensor plate is level and does not move;
• As soon as the coolant temperature increases (reaches a certain level), the plate is deformed and the contacts close.

It is noteworthy that on different car models the DVVs are set to one or another activation temperature.

There are two types of DVVs: those designed for 1 rotation speed and models designed for 2 rotation speeds.

The fan runs when the ignition is turned on.

As a rule, all modern cars are equipped with DVV with a 1-speed activation system, although 2-speed sensors are not uncommon. It will be interesting to note that on such a DVV, when a certain degree level is reached, the fan turns on to the first rotation speed. The second speed is activated and the fan speed increases accordingly when the coolant temperature continues to rise.

Damage to the engine is not only problems when turning on the ignition, but also overheating of the engine and other unpleasant moments. For this reason, first of all, if the fan turns on when you turn on the ignition, you should test the functionality of the sensor.

You can test the functioning of the DVV yourself. To do this, you need to hang the removed sensor over a pan filled with water. Connect the DVV in advance with two wires to a continuity tester (multimeter).

Attention. The metal part of the DVV should be immersed in water. In addition, the sensor should not come into direct contact with the pan.

The DVV should be triggered when the water in the pan heats up. It is recommended to study the technical specifications of the DVV in advance in order to properly test the sensor. For example, some of them are designed to turn on after 93 degrees Celsius, others - after 100 degrees, etc.

Why does the VAZ 2114 fan constantly work?

What to do if the VAZ-2114 injector

It should be emphasized that if the car is moving at high speeds, then there is certainly no need for the fan to operate. But since the car's speed decreases even when the car is idling, you simply cannot do without a fan.

This device turns off automatically because it receives a signal from the electronic control unit. After stopping the VAZ 2107 fan because it is not working, turn the inside of the radiator. This signal is based on data received from a temperature sensor, which is activated when the coolant temperature rises to 103 degrees.

Possible reasons for refusal

If the fan on the VAZ-2114 (injector) does not work, this may be due to the following reasons:

1. The fan motor has failed.
2. The fuse requires replacement.
3. no works .
4. The wiring was disconnected.
5. There is no contact in the temperature sensor connector.
6. Temperature sensor malfunction

Find possible causes of fan failure

What to do if the cooling fan operates on a cold engine

Drivers often ask questions when the cooling fan turns on on a cold engine. The problem mainly occurs due to certain malfunctions in the cooling system. For example, many cannot understand the reason when the fan starts to turn on on a cold unit.

Timely prevention will help avoid more serious problems. Since if you do not pay special attention and do not repair the fan, then in the future, you can cause the motor to overheat. In frequent cases, the use of an adapter is required to carry out a thorough diagnosis.

By eliminating the main cause, fan short circuits can be avoided. Many experts believe that the process is quite easy, so every person can determine the malfunction of the device in his own garage. This common question plagues many people who are faced with an unpleasant problem. But first, you need to understand the principle of operation of a system that gradually fails.

It is worth noting that the fan is connected using a sensor. This important element is located at the bottom of the radiator. More modern models are equipped with special triggers, which, in turn, pass through the unit control unit.

However, this occurs in rare situations. Therefore, let's consider another option. Complete heating of the coolant reaches at least one hundred degrees. Accordingly, the circuit closes, after which the fan itself turns on. In such a case, you need to look for the cause in breakdowns. Because when the cooling system deteriorates, more serious problems may arise in the future.

The fan runs on a cold motor: causes, diagnosis, repair

Let's start with the fact that this problem can clearly indicate both a malfunction of the liquid cooling system and a malfunction of the fan itself. In any case, we are talking about a breakdown that cannot be ignored, since the risk of overheating of the internal combustion engine significantly increases.

For a better understanding, it is necessary to superficially consider the principle of operation of the fan on most modern cars. The airflow is activated by a special sensor located at the bottom of the radiator. Also, many cars use a separate engine cooling fan control unit. There are also models in which the ECU itself is responsible for turning on the fan, but this design is rarely used.

As you can see, the fan should not work on a cold engine. So, to determine why the fan turns on early, for injection cars with an OBD II diagnostic connector, it is recommended to start with computer diagnostics of the car. The fact is that the ability to read error codes from the ECU allows you to more accurately determine the cause of the malfunction.

We also note that in cases where the control unit detects errors in the cooling system, the fan can spin immediately after turning on the ignition, even on a cold internal combustion engine. This feature is found only on some models and is, in fact, protection against overheating of the power unit, since a constantly running fan reduces the temperature.

After repair, in this case you will also need to reset the errors. To erase an error from the ECU, on some models it is enough to remove the terminal from the battery for a couple of minutes, while on others the reset is carried out using diagnostic equipment.

Common cooling fan problems

Now let's look at common problems that are associated with the cooling system and the fan itself.

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

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.

Why is the cooling fan constantly running?

If the engine fan runs constantly, there may be 7 reasons for this.

Coolant temperature sensor

• Failure of the coolant temperature sensor or damage to its wiring . If incorrect information is sent from the sensor to the ECU (high or low signal, its absence, short circuit), then errors are generated in the ECU, as a result of which the control unit puts the engine into emergency mode, in which the fan “threshes” constantly to prevent overheating engine. You can tell that this is the problem by the difficulty of starting the engine when it is not yet warmed up.
• Shorting the wires to ground . Often the fan runs constantly if its negative wire is frayed. Depending on the engine design, this may be in different places. If the design of the engine provides for two DTOZH, then if the “minus” of the first sensor breaks, the fan will “thresh” when the ignition is on. If the insulation of the wires of the second DTOZH is damaged, the fan runs constantly when the engine is running.
• Faulty fan relay . For most cars, the fan power supply consists of “plus” from the relay and “minus” from the ECU according to the temperature from the DTOZH. “Plus” is supplied constantly, and “minus” is supplied when the antifreeze operating temperature is reached.
• "Glitches" of the electronic control unit . In turn, incorrect operation of the ECU can be caused by a failure in its software (for example, after flashing) or when moisture gets inside its housing. The moisture could be banal antifreeze that got into the ECU (relevant for Chevrolet Cruze cars, when antifreeze gets into the ECU through a torn throttle valve heating tube, it is located near the ECU).
• Dirty radiator . This applies to both the main radiator and the air conditioner radiator. In this case, the fan often runs constantly when the air conditioner is on.
• Freon pressure sensor in the air conditioner . If it fails and if there is a refrigerant leak, the system “sees” that the radiator is overheating and tries to cool it using a constantly turned on fan. Some car enthusiasts have a cooling fan that constantly runs when the air conditioner is turned on. In fact, this should not be the case, since this indicates either a clogged (dirty) radiator or a problem with the freon pressure sensor (freon leak).
• Low efficiency of the cooling system . Failures may be associated with a low coolant level, a coolant leak, a faulty thermostat, a pump failure, or a depressurized radiator cap or expansion tank. With this problem, the fan may not work constantly, but for a long time or turn on frequently.

What to do if the cooling fan is constantly running

When the engine cooling fan runs constantly, you should look for the problem by doing a few simple diagnostic steps. The check must be performed sequentially, based on the most probable causes.

Conclusion

Most often, the radiator cooling fan spins constantly due to a short circuit in the start relay or its wiring. Other problems are less common. Accordingly, diagnostics should begin with checking the relay, wiring and the presence of errors in the ECU memory.

Source

Fan diagnostic method

Experts say that injection cars are considered the most practical. They can be diagnosed much faster than all others. It is advisable to use computer diagnostics to thoroughly investigate the cause of all malfunctions. Some models, when making errors, immediately show a constantly spinning fan. This helps protect against overheating.

To reset errors, you need to remove the terminal from the battery for a few seconds. After the system is cleaned, everything returns to normal.

DD or pressure sensor

You should be aware that on some cars where the air conditioning is turned on, 2 sensors are used in the fan activation circuit. One of them is the DVV, but it is more correct to call it a temperature sensor, because it turns on the fan based on the temperature readings.

The second sensor is a pressure regulator or pressure regulator. If the DVV is in front of the thermostat, then the DD is in the air conditioning system on the high pressure line. It operates and is activated exclusively by pressure up to 15 bar. Accordingly, if the pressure rises above this value, an additional car fan turns on.

Why does the fan turn on when the ignition is turned on?

Thus, if the air conditioner or fan turns on when you turn on the ignition, this may indicate a failure of the pressure sensor.

It is also likely that the chip was disconnected. This often happens by accident, due to the fact that in some cases the DD is placed near the battery, next to the filling channels.

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.

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.

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.

What to do if the cooling fan on the VAZ-2110 does not turn on

The VAZ-2110 is often called the “ten” among drivers. Among such vehicles, one of the main problems is the breakdown of the heating and cooling system. The problem is unpleasant and causes considerable trouble for its owner, but it is quite easy to deal with it even with your own hands, without contacting a service center, and you will save a considerable amount. This article will tell you what to do if the cooling fan on the VAZ-2110 does not turn on. On average, a new purchased cooling fan for a VAZ-2110 ranges from 1 to 2.5 thousand Russian rubles. However, replacing its individual faulty parts will cost much less.

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.

Weight

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.

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

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.