VAZ 2109 injector cooling fan does not work

Driving for a long time on an overheated engine when the VAZ 2109 injector cooling fan is not working is fraught with serious consequences. The motor may knock or jam, and then major repairs will be necessary. Therefore, if the temperature sensor needle moves steadily into the red zone, immediately turn on the heater at full power, stop in a safe place and let the engine cool. Do not open the expansion tank cap on a hot engine; overheated antifreeze may splash on you.

What to do if the cooling fan on a VAZ-2109 does not work

From the moment electric fans began to be used on VAZs with carburetors, car enthusiasts often began to experience their failure.
Previous mechanical models were considered almost eternal. In most cases, when a VAZ-2109 fan with a carburetor is said to not work, the unit completely stops performing its functions. In this case, the engine temperature exceeds 100 degrees, and the car may fail. To avoid major repairs of the power unit, it is necessary to stop driving after the temperature needle deviates into the red zone. Then you need to find the reason why the fan is not working. You should start checking with the liquid level in the cooling system (check the expansion tank), and then gradually eliminate faults in other parts of the system:

fuse;
temperature sensor;
electric fan motor;
impeller (it can be deformed, which leads to jamming).

While performing work, you will have to check the condition of the power circuit along the way. All conductors should be visually normal. It is best to eliminate the probable causes of failure one by one so that the system operates stably.

How to check a fuse
Checking and replacing the temperature sensor
Checking and replacing the electric motor
How to change the impeller or align it

General characteristics of the model

Dream car in the 90s

The dimensions of the car have changed somewhat due to the lengthening of the wing and enlargement of the hood. In addition, a completely new, improved VAZ radiator grille and, of course, an updated dashboard appeared. The length of the VAZ 21099 compared to other cars in this group has increased by 20 cm.

The VAZ 21099, like other models of this family, has many advantages:

it is capable of developing a fairly high speed;

has excellent controllability when driving;

Stable on completely different types of roads.

In 2004, this model of car was no longer produced in Russia, but its production continues in Ukraine.

VAZ 21099 cars come in two types. The VAZ 21099 has a carburetor, just like the VAZ 21099 has an injector, the layout of the fuel supply system is almost identical.

In the VAZ 21099 injector, the supply of gasoline when you press the gas pedal is controlled by a computer. In a carburetor engine, such emissions are controlled by special damper plugs.

Quite often, the owners of this car are faced with one problem: the VAZ 21099 carburetor cooling fan does not work.

How to check a fuse

This is the simplest part of the test, suitable if the power plant is equipped with a carburetor. You need to find a mounting block in the engine compartment of the VAZ-2109. In it, in place of F-4, there is a fuse responsible for the operation of the cooling fan. Pull it out of its seat, and then use a multitester to take a test measurement (performance test).

If the fuse is working, look for another fault. Otherwise, you need to put a new one in its place marked 16 A and run it in. If the fan is working, you don't need to do anything else. Otherwise, examine other parts of the cooling system.

Frequent causes of fan failure on VAZ 21099

In order to carry out manual diagnostics and identify a fan failure on a VAZ 21099, you need to know the basic list of the most common causes of this malfunction.

Failure of the electric fan drive.
Fuse failure.
Relay failure.
Possible electrical wiring breaks.
Problems with the temperature sensor (no contact).

To conduct manual diagnostics to identify this problem, you need to start by searching for the causes, which anyone can do.

Checking and replacing the temperature sensor

On a VAZ-2109, the cause of untimely operation or complete failure of the fan is often the coolant temperature sensor. Therefore, it needs to be checked secondarily. The sensor is located at the bottom of the radiator, two wires come from it. Before unscrewing it, you need to accurately check the operation of the cooling system:

Connect the ends of the wires leading to the sensor together. If after this the fan starts working and the sensor gets hot, then this controller needs to be changed. When testing on a hot radiator, you may find that the sensor body is also warm. In this case, check the thermostat.
If the fan does not work even after shorting the wires, then the problem may lie in the relay or fuse. The relay should be checked if the sound of its operation is not heard. Depending on the type of car, it may be located in the mounting block (for models with carburetors) or in the passenger compartment under the driver’s storage compartment (for injection cars). The easiest way to check this device is to install a similar device in its place. If after replacing the relay the fan starts working, you don’t have to carry out further testing.
Sometimes the device does not work, but the sound of the relay operating is present. In this case, check fuse F-8.

If you do not find any faults in other systems, then you need to replace the temperature sensor in the cooling system. This is done according to the instructions:

Turn off the ignition, remove the terminal from the battery and drain the fluid from the expansion tank and the generator. To do this, you need to remove special plugs.
Then disconnect the sensor from the terminal block.
Using a spanner wrench, unscrew the sensor from its place without applying excessive force.

Install a new sensor and reassemble. Some car enthusiasts prefer not to drain the antifreeze from the system, but simply act quickly. In this case, after the sensor leaves the seat, a certain amount of coolant will leave the system, so it will need to be topped up.

Electric fan connection diagram

The electric fan is turned on using a temperature sensor installed in the radiator. Some cars have an additional sensor in the engine block that turns on the fan at reduced speed. This is done by powering the motor winding through a resistance. The control scheme may also differ on different cars. The simplest circuit consists of the fan itself, a fuse, a temperature sensor and connecting wires.

The fuse is selected based on the fan power. And the sensor acts as a power switch. As a rule, the sensor is installed in the gap of the negative wire. For example, on the VAZ 2109, starting in 1996, exclusively this switching scheme was used. The designers made a small mistake, since the wire that goes from the sensor to ground is very long. During operation, it may become damaged, causing the entire circuit to stop working.

The temperature sensor may also fail, this is not uncommon. To replace it, you need to drain the coolant from the radiator, since the sensor is located in the lower part of it on most cars. The electric fan control circuit, which uses an electromagnetic relay, is a little more complicated, but due to this relay itself it has less reliability. An extra part that can fail at the wrong time. But on the other hand, the sensor has low currents; all the high current passes through the relay contacts.

Checking and replacing the electric motor

If after replacing the sensor the fan still does not work, then it is necessary to check and replace its electric motor. But first you need to dismantle it:

Remove the negative terminal from the battery.
Disconnect the fan from the power circuit (one of the blocks is located on its casing).
Unscrew the mounting screws from the device casing: left and bottom.
Using a socket with an extension, remove the fasteners connecting the casing to the generator.
Remove the two nuts on the left to remove the fan pressure spring. Take it off.
Pull out the entire assembly, along with the housing. Along the way, you may need to disconnect its wires.

Now you need to get to the electric motor and install a new one in its place:

The electric motor wire is secured to the housing with a clamp; disconnect it.
Then unscrew the three nuts to remove the motor.
Inspect the motor seat; all rubber pads on it should be intact and not deformed. If you notice damage, install new gaskets.
After this, you need to install a new motor in place of the old one and reassemble the fan.

Some car enthusiasts believe that it is possible to repair the engine, but in most cases their attempts do not lead to success.

How to change the impeller or align it

If, after dismantling the fan, you notice that the impeller is damaged or uneven, you need to remove it:

There is a lock washer in the center of the impeller; pry it up with a flathead screwdriver and remove it. If there is an additional fastening in the form of a nut, unscrew it.
Remove the impeller and inspect it. If there is any deformation, it is best to install another impeller.

During this work, you can upgrade the fan by installing an impeller with 8 blades instead of the standard 4.

Examination

On VAZ 2109 engines, the operating temperature is 90 degrees.

If the indicator needle crosses the 100 degree mark, the car should be stopped immediately, the engine should be turned off and the power unit should cool down. Without doing this, you risk major, expensive engine repairs.

The motor can overheat for various reasons:

The thermostat has failed;
The radiator is clogged;
The radiator fan has failed;
The fan switch sensor is broken;
The coolant level in the system has dropped;
The pump has failed;
The integrity of the wiring in the fan circuit has been compromised.

All these reasons can and should be checked before purchasing new parts.

Here is an example of checking a fan and sensor.

Object to be checked

Method

Take one wire about a meter long. Preferably with two crocodiles at the ends. The mass goes to the fan. Your task is to supply voltage directly from the battery to the fan. Apply 12 volts to the second contact of the fan. If he's spinning, he's fine. If not, you'll have to change it

Turning on the ignition, close the sensor contacts with a screwdriver. Normally, when it is closed, the fan should start spinning, and if it is open, it should stop. Please note that different types of sensors have a certain response temperature - from 87 to 90 degrees or more

Checking the inclusion of the fan on the VAZ 2111 engine

In case the injection engine gets hot, you should first check the fuse protecting the electric fan circuit, then the auxiliary relay. The cooling fan relay can be found in the passenger compartment on the passenger side under the glove compartment. At the same time, make sure that the fan motor is activated in forced mode.

In addition, the electric fan on the VAZ 2111 engine is turned on according to data from a sensor located on the engine exhaust pipe. However, to determine the malfunction of this sensor, service computer diagnostics is required.

VAZ 2111 - antifreeze boils, the electric motor of the engine cooling system fan does not turn on, causes and solutions
Cooling system 2108 – Encyclopedia of the magazine “Behind the wheel”
Maintenance, installation and repair of VAZ 2108, 2109, 21099 cars – Electric motor of the engine cooling system fan
VAZ 2108, Checking the cooling system fan relay, Lada Samara

Sensor

Don't rush to change the fan right away. Often the problem was a sensor, relay, fuses, or simply broken wiring. First of all, we will check the sensor and also tell you about the features of replacing it.

The fan switch sensor is located at the bottom of the radiator. A couple of wires come off it.

Searched device

Accurate check

In order not to rush to conclusions, experts first advise checking the sensor for functionality.

If the fan does not want to turn on according to the standard circuit, try shorting the wires that go to the sensor. If the fan is running and the sensor is hot, the problem lies there. If the radiator is hot during testing, the sensor housing may be warm. This suggests that you should check the condition of the thermostat and the coolant level in the tank. You may need to change and top up accordingly.
If, after closing the wires, the fan does not turn on, the sound of the relay being activated is not observed, check the condition of the relay and fuse. It is number 4 in the mounting block.
By shorting the wires, the fan did not start, but the relay worked. Here you should check fuse number 8.
If the fan starts randomly on a cold engine, it does not turn off for a long time, try disconnecting one wire from the sensor. If the fan stops, the sensor contacts are stuck. If the fan continues to turn, sticking has occurred on the contacts of the control relay.

Having discovered that the regulator has failed, there is nothing left to do but change the radiator fan activation sensor.

Replacing the sensor

Changing the sensor is quite simple:

Turn off the ignition;
Drain the coolant from the expansion tank;
Disconnect a pair of wires from the sensor terminal block;
Using a 30 mm wrench, unscrew the regulator from its seat. You shouldn’t apply a lot of force; you risk breaking the seat;
Following the reverse sequence, install the new sensor.

Disabling the sensor

You can change the sensor without draining the coolant. To do this, you need to quickly unscrew the old regulator and screw in a new one in its place. A small part of the coolant will spill out, but you won’t have to drain it for a long time and then pour it back in.

Troubleshooting on VAZ 2108 and VAZ 21083 engines

Thus, to eliminate a malfunction on a carburetor engine, you must first check the integrity of the fuses in the mounting block. Burnt fuses are easy to see with the naked eye. On cars produced before 1998, the electric fan relay should also be checked. If it is found that there is electrical contact between terminals “c” and “b” or no contact between “c” and “d”, the relay must be replaced.

Also, do not exclude the possibility of failure of the sensor installed in the car radiator, as well as the electric fan itself. In order to test their functionality, it is enough to remove the contacts from the sensor and close them together. If the cooling fan starts working, it’s all in the sensor, but no, the problem lies in the electric fan motor.

Fan

If the problem lies in the injector or carburetor cooling fan, then you will have to remove it. It is quite possible to repair the unit by replacing the electric motor or impeller.

Diagram with casing, radiator, fan and impeller

To remove the valve, perform the following operations:

Disconnect the negative terminal from the battery;
Disconnect the wire terminals. One of them is mounted on the fan casing;
Take a wrench and unscrew a couple of connecting bolts. They fix the vent casing on the left tank;
Next, unscrew another lower nut holding the device casing;
Now you will need a socket extension to unscrew the right nut on top that secures the vent housing to the radiator;
All that remains is to unscrew the fan pressure plate. To do this, remove the pair of left nuts;
Remove the pressure plate by hand;
Now remove the fan along with the casing.

You have removed the unit. Now you have a choice - change the entire unit, or try to repair it by replacing the electric motor or impeller if they are damaged.

Replacing the electric motor

Disconnect the fan motor wire that is held in place by a clamp on the casing.
The electric motor is held on the casing by three nuts. They all need to be unscrewed.
Remove the electric motor from the fan housing.
Be sure to check the condition of the rubber bushings of the electric motor, which will remain on the casing. If cracks or signs of deformation are detected, they must be replaced.
Check the electric motor for functionality. If it fails, you can purchase a new one and insert it into the old casing.

Electric motor

It is not uncommon that the performance of a radiator fan is impaired due to a deformed impeller. By replacing it, you can restore functionality to the device.

Replacing the impeller

To change the impeller, follow the instructions:

Pry up the lock washer using a flathead screwdriver. It is located directly in the center of the impeller;
Lift the washer and remove it;
In some cases, the impeller is secured to the fan motor with a nut. Therefore, if you have one, unscrew the mount;
Remove the impeller and assess its condition. If it is worn out or deformed, replace it with a new one;
Many people, instead of a standard 4-blade impeller, install a more advanced 8-blade impeller.

Changing the impeller

During reassembly, make sure that the motor pin fits into the longitudinal hole on the impeller, as shown in the figure below.

Direct the pin into the longitudinal hole

Finding the problem

On injection engines the situation is different: the fan is controlled by a relay, but activation depends on the engine control unit.

Often the problem may simply be the fan cooling relay. For injection VAZ 21099 it is located in the passenger compartment in the glove compartment. The cooling fan relay is located to the right of all the others.

In carburetor engines, you need to find the fuse box. It is located under the hood on the left in front of the windshield. You need to find fuse mounting block 17.3722. The cooling fan relay is located in the second row. It is third from the right in this row. If the required fuse has burned out, it will be visible to the naked eye.

For VAZ 21099 produced before 1998, the situation may be slightly different. The relay does not turn on when there is an electrical discharge between terminals “c” and “b” or when there is no contact at terminals “c” and “d”.

The cause may also be a failure of the coolant temperature sensor. On carburetor engines it is located to the right of the radiator. On injection engines, the coolant sensor is located in the cylinder head exhaust pipe.

Its functionality can be checked in this way:

Place it in some container filled with coolant.
Connect the sensor to the multimeter
Next, increase the coolant temperature to a certain temperature and check the resistance indicated on the multimeter.

At a coolant temperature of 100, the resistance that appears on the multimeter will be 177 Ohms.

at 80 – 332 Ohm;
at 60 – 667 Ohm;
at 40 – 1459 Ohm;
at 20 – 3520 Ohm;
at 0 – 9420 Ohm;
at -20 – 28680 Ohm;
at -40 – 100700 Ohm.

If the sensor turns out to be faulty, then replacing it is not very difficult. To do this you need:

Turn off the ignition.
Drain the coolant from the expansion tank.
Disconnect the wiring from the sensor.
Using a 30mm wrench, carefully unscrew the sensor so as not to damage the socket.

If the sensor and relay are working properly, inspect the wiring. It could have collapsed somewhere due to corrosion.

It may turn out that the problem lies with the fan itself. You can fix it yourself by replacing the fan motor or impeller.

Fan removal procedure:

Disconnect power from the battery.
Disconnect the wiring terminals. One of the pads is on the fan.
Unscrew the connecting bolts securing the fan casing with a wrench.
To unscrew the right nut located on top of the fan, you need a cap socket and an extension.
Next you need to remove the pressure plate. To do this you need to unscrew the two left nuts.
Remove the pressure plate yourself.
Next, remove the fan and shroud together.

Modernization

If you want to improve the operation of your radiator fan on the VAZ 2109, we offer the appropriate instructions.

To upgrade, you will need to install a second sensor and modify the system somewhat.

The standard power sensor will be responsible for the operation of the fan at maximum speed.
An additional sensor will include a reduced speed. It is installed at the top of the cooling system.

Now let’s talk more specifically about how to organize all this.

Take a temperature sensor whose response temperature is similar to the standard regulator.
Install it in the upper pipe fitting to the radiator.
To mount the element, you will need a pair of washers and a nut. Be sure to lubricate the washer with sealant to prevent leakage from the installation hole.
Buy a resistor to install on the stove fan. It has several outputs, so if desired, you can make several operating speeds.
It is necessary to make an additional control circuit. Through it, less voltage will be supplied to the motor winding.
The temperature sensor located in the upper part of the cooling system is responsible for turning it on.
It is better to do control not by plus, but by weight.
The system will work through a button in the cabin. To the left of the dashboard there is a grille with two plugs. Cut out one of them and set it to turn off on two modes. You can take the heater switch from a VAZ 2107.
In the first position the low frequency will be switched on, and in the second – the maximum speed.
One common wire is fed to the minus.

Such modernization is not provided for by the design of the VAZ 2109. These are modifications made by car enthusiasts. Therefore, installing a second sensor is entirely your personal responsibility.

The fan is an important component of the cooling system of VAZ 2109 injection and carburetor engines. If you wish and have time, you can easily replace or repair it yourself.

What to do if the fan fails?

The simplest case is a blown fuse. To restore, you just need to find its location according to the diagram and replace it with a similar one. You cannot install a fuse whose operation current is much greater than it should be. The same applies to “bugs”. But if the temperature sensor fails, you will have to act with an eye on the current situation. If you are moving along the highway, then the flow of oncoming air should be enough for cooling.

But if you are driving around the city, then the best solution would be to short-circuit the sensor terminals. The same should be done if a relay is installed in the control circuit, but it burns out. But if the damage is somewhere in the wiring, then the best way out of the situation is to connect the fan to the battery terminals. Just remember to turn it off before turning off the engine.

The reasons for radiator fan failure are related to its electrical or mechanical part. As a result, under certain conditions, the car engine begins to overheat.

Causes of the malfunction: “the radiator fan does not work” of the cooling system

Using the example of the radiator fan of the carburetor engine cooling system of VAZ 2108, 2109, 21099 cars.

— The radiator fan sensor has failed

On carburetor VAZ 2108, 2109, 21099 and their modifications, the sensor is located on the right radiator tank. Its failure is the most common cause of radiator fan failure. Turn on the ignition. We close the sensor contacts with a piece of wire (do not remove the wires from them). If the fan starts working, the sensor is faulty, if not, its electrical circuit is faulty.

— The electrical circuit of the sensor is faulty

The radiator cooling fan does not turn on - reasons, troubleshooting

Problems with the cooling fan usually occur in used cars with decent mileage. This breakdown manifests itself in different ways; the fan may not work stably, may turn on late or not turn on at all. Today we will talk about the last fault, that is, the situation when the cooling fan does not turn on at a certain moment. You will learn about why this happens, where to look for the reason, and also in what sequence. Let’s take the “nine” as an example, but the method and reasons will be almost the same for all VAZ models.

Finding a breakdown is not so much labor-intensive as it is comprehensive, since there can be quite a few reasons why the fan does not turn on, from a banal fuse blown to more complex problems associated with a malfunctioning thermostat or problems with the electrical wiring of the vehicle’s on-board network.

If the engine boils, but the fan still does not turn on, then the first thing that comes to mind for most motorists is problems with the fan wiring. However, very often the wiring has nothing to do with it, and the real reason lies precisely in the thermostat. The device designed to monitor the temperature of the coolant (coolant) may fail or simply jam, after which the coolant stops circulating through the radiator, as a result, the radiator sensor does not work, and the fan itself does not turn on. Read this article on how to check the thermostat.

Causes of fan malfunction

There are times when the radiator cooling fan runs continuously. This is also wrong. What to do in this case? What is the cause of the malfunction?

There may be a broken circuit in the temperature sensor. This will be indicated by a constantly lit sensor light. In this case, you simply need to replace the temperature sensor or the injection system unit. The relay may need to be replaced. Also, the contacts on the radiator thermal switch that triggers the relay may not open. To fix the problem, you will need to replace the thermal switch.

To find out the cause of the fan malfunction, you will need to remove it.

Disconnect the fan block and harness by disconnecting the wires.
Disconnect the motor wire by unscrewing the left nut. If necessary, use suitable keys.
Under the hood, unscrew the two screws that secure the fan.
Take out the casing.
Remove the two fan mounting bolts.
Remove five more bolts and the air intake grille.
Lift the fan support and pull it towards you.
Rotate the fan itself 90 degrees and remove it.

Fan motor connection diagram

If there is any breakdown in the car, regardless of whether the fan has stopped working or something else, you should contact a specialized workshop. Experienced technicians will always find the cause of the problem, select suitable parts, sensors and carry out repairs. Of course, many car owners want to repair their vehicles themselves; this gives them a lot of pleasure and requires minimal costs. But in this case there is a risk of making a mistake with the selection of parts and the correct diagnosis. A car enthusiast can spend a lot of effort and time, but in the end do not get the desired result. To prevent this from happening, it is better to contact a specialist.

Radiator fan of VAZ 2109 Injector does not work

If the VAZ 2109 fan does not work

Driving for a long time on an overheated engine when the VAZ 2109 injector cooling fan is not working can cause serious damage. The engine may cause other damage, in which case it will require major repairs. Therefore, if the temperature gauge needle constantly moves into the red zone, immediately turn on the heater at full power, stop in a safe place and allow the engine to cool. Do not open the expansion tank cap on a hot engine; it can be sprayed with superheated antifreeze.

VAZ 2109 cooling system

VAZ Liquid engine cooling system 2109 The nozzle is a closed type system with forced circulation of antifreeze (coolant). The system consists of the following blocks:

water pump with impeller driven by a timing belt;
a thermostat that directs coolant to a small, in other words, a large circle, depending on the degree of engine warm-up;
a radiator consisting of two plastic containers for coolant flow and aluminum heat pipes located in the front of the engine compartment to facilitate air access;
expansion tank with inlet and outlet valves to maintain standard pressure in the system;
fan
in front of the radiator for efficient heat dissipation.

The VAZ 2109 carburetor fan does not work.

Running the fan is critical in the heat of the year when you're moving slowly in traffic. Under these conditions, overheating of the engine is especially possible and, therefore, good fan operation is necessary. The cooling air flow must be properly directed to the radiator

. If the VAZ 2109 injector cooling fan does not work, the cooling system may boil.

Fan control

If the car is a VAZ 2109

If the engine has separate injection and injector, then there is no common touch switch for carburetor model owners. The ECU fan controller turns the fan on and off. This controller receives information from a coolant temperature (DTO) sensor located in the exhaust pipe between the thermostat and the cylinder head. The sensor is used to control not only the fan, but also the motor. Including:

optimization of the degree of enrichment of the air-fuel mixture: in a cold engine the mixture is enriched again, and when heated, it is depleted;
increasing the crankshaft speed when starting the engine so that the engine does not lag immediately after starting;
setting ignition timing to ensure fuel economy;
holding the recirculation valve in the closed position until the engine is in running mode.

Why doesn't the engine cooling fan work in 2114?

VAZ 2109 fan, fan fan, does not work.

fan

cooling
radiator
.

To determine the temperature of the VAZ VAZ 2109 , a thermistor is used in the injector. a resistor whose resistance depends on temperature. VAZ 2109. A thermistor with a negative temperature coefficient is used. This means that as the temperature increases, its resistance decreases.

Voltage is applied to the thermistor; By changing it, the sensor determines the temperature of the coolant and transmits it to the computer. And this device already turns the radiator fan on and off.

Fan diagnostics

To test the device, you will need a 1.5-meter wire, preferably with crocodile clips at the ends. With the engine off, connect the positive terminal of the battery directly to the fan terminal. The working unit should begin to rotate. Startup error is faulty. If the engine does not start when the engine fan

Although the diagnosis indicates that they are in good condition, they should be tested for DTH.

During the test, you will need an ohmmeter to measure the resistance of the sensor. An ohmmeter is part of any, even the simplest, portable digital multimeter. The procedure looks like this:

With the engine cold, remove the wires from the DTO terminals.
Set the multimeter mode switch to the “resistance measurement” position.
Measure the sensor resistance. At room temperature it should be approximately 2200-2800 Ohms.
Replace sensor wires.
Start the engine and let it idle at about 80 degrees Celsius.
Turn off the engine. Remove the wires from the sensor contacts.
Measure the sensor resistance. At 80 degrees the resistance should be in the range of 270.389 ohms.

Coolant temperature sensor for VAZ 2109 and 21099 cars

First, it is advisable to know where the engine temperature sensor is located. On models 2108, 21099 and VAZ 2109, the coolant temperature sensor is installed between the cylinder head and the thermostat, in the exhaust pipe.

Device and principle of operation

The engine temperature controller itself is a thermistor-resistor device characterized by a negative temperature coefficient. The resistance parameter itself can be measured only when the temperature decreases or increases.

When the power unit heats up as a result of operation, the resistance indicator decreases; if the engine cools down, this parameter increases. For example, at the operating temperature of the engine on a VAZ 2109, the resistance is equal to 180 Ohms, and if it is 40 degrees cold outside, then the resistance will be equal to 100,700 Ohms. On one side of the DTOZH VAZ 2109 injector there are two contacts, and on the other there is a sensitive component, which is located directly in the flow of consumables.

As for the principle of operation, when the driver turns on the ignition, the control unit transmits voltage to the regulator via a resistor. Since the DTOZH itself is a thermistor, the voltage supplied from the control unit changes immediately taking into account the temperature of the consumable. When the parameter decreases, the unit analyzes the temperature and, in accordance with these data, determines the required volume of gasoline for injection. As the power unit warms up, the volume of gasoline that is transferred to the cylinders will decrease.

Two antifreeze temperature sensors for VAZ

In addition to starting, according to the readings of the regulator, the ECU adjusts the operation of the power unit at idle speed. As a result, he independently makes decisions on enriching the combustible mixture at high and medium loads on the internal combustion engine. This indicator can be changed depending on the ignition timing.

There are two temperature sensors on a carburetor car. One turns on the fan, the other is responsible for indicating the temperature on the dashboard.

Possible faults

There are several reasons why the regulator on the VAZ 21099 refuses to work.

So, why DTOZH does not work:

An electrical contact is located inside the device structure. Over time, this contact may simply break or cracks may form on it. If a break occurs inside the structure, this may cause complete failure. That is, the DTOZH will simply burn out. If there are cracks on the contact, the DTOZH, in principle, can work, but as a result of the lack of normal contact, the regulator will transmit incorrect data about antifreeze.
Poor device insulation. If the insulation is broken, short circuits may occur in the operation of the device. Accordingly, ultimately, these short circuits can lead to the DTOZH, again, burning out and having to be replaced.
There was a broken wire near the regulator. As a result of the break, the regulator will not be able to activate the fan designed to cool the power unit. Accordingly, this will lead to the engine overheating and may even boil (the author of the video is a Mechanical Technician).

Why the fan does not work - VAZ 2109

Two fans are installed on the VAZ-2109 car . The first, more powerful, is installed in the engine cooling in order to increase air flow through the radiator core. The second fan is installed in front of the heater radiator (“stove”) , its task is to pump heated or unheated air inside the car. Both fans are driven by DC motors.

The fan, which is installed in the hole in the casing covering the radiator core in the electrical circuit for its connection, has a sensor for automatically turning on the electric motor. This sensor is screwed into a threaded hole located in the right radiator tank, since there will be the highest coolant temperature after the thermostat is activated. The fan starts working without driver intervention. The sensor should be triggered when the operating temperature of the antifreeze exceeds 90-95 degrees and send a signal to the electric motor switching relay located in the mounting block. The electrical circuit for switching on the electric motor is protected by fuse No. 4 and No. 8 on mounting blocks of type 17. 3722.

If your VAZ-2109 car is equipped with a mounting block of type 2114-3722010-60, then the fan electric motor is switched on directly from the switch-on sensor, without the participation of a relay. It's just not in the mounting block at all. The electrical circuit is protected by a fuse designated No. 5. In the event of any malfunction in these electrical circuits, the fan will not turn on. The driver will determine this by reading the coolant temperature gauge. The arrow of this indicator will go to the red zone of the scale. In this case, it is necessary to reduce the load on the engine to idle speed, turn on the interior heater fan and open the tap to supply coolant to the heater radiator, start coasting until it comes to a complete stop, to eliminate the causes of the malfunction.

It is necessary to start looking for the cause of malfunctions from motor activation sensor . To do this, open the hood and disconnect the terminal from the sensor. To further check the sensor, you will need a piece of wire, with which you need to short-circuit the two wires suitable for the terminal. Wrap the jumper with electrical tape so that it does not touch the ground of the car. Turn on the ignition, and if everything else is correct, the fan will start working. Moreover, in this case it will work continuously as long as the ignition is on.

If the fan on the VAZ 2109 does not work, then open the cover of the mounting block and check the serviceability of fuses No. 5 on block 2114-3722010-60 and No. 4, No. 8 on block 17. 3722. Look for the fuse number marking on the top of the cover. After making sure that the fuses are in good condition and provided that the fan still does not work, you need to check its electric motor.

To do this, you will need two insulated wires to connect the fan motor terminals directly to the battery. If the fan starts working, make sure that the air flow goes under the hood of the car, and not vice versa. If the connection is incorrect, change the polarity of the wires connected to the battery. When troubleshooting, you can thus get to the repair site, and you can turn off the fan motor only by disconnecting the wires from the battery. In this case, the reason that the fan did not turn on would be either a faulty relay or a faulty wiring.

In order for the driver not to be left alone with such malfunctions, he needs to have in the trunk of his car a coil of car wires three meters long and a supply of fuses , which are located in the mounting block.

Fan activation principle

The fact is that on VAZ 2108 and 21083 engines the electric fan comes into action thanks to a sensor installed on the right side of the cooling radiator. The fan is switched on directly when its contacts are closed at a temperature of 99°C. On cars manufactured before 1998, the sensor controls the fan through a special relay 113.3747 located in the mounting block. And on the VAZ 2111 injection engine, the cooling fan operates only through a relay based on a signal from the control unit.