For VAZ-2107 cars, over the years of their production, both carburetor and subsequently injection engines were installed. Therefore, the electrical circuits for supplying voltage to the engine cooling fan motor are different from each other.
On injection VAZ-2107 engines, a two-contact fan sensor, which is located in the upper pipe, when the coolant temperature rises above that for which it is designed, it should send a signal to the computer. The electronic control unit, having analyzed the signal, turns on the fan through the relay.
Therefore, the search for reasons for not turning on the fan begins with removing the connector from the sensor, with the ignition on. If the fan itself is working, then it should work. By inserting a load in the form of a light bulb into the connector terminals, the fan should stop. Thus, you check the electrical circuit of the fan motor. In this case, it will be serviceable, and the fan sensor will have to be replaced. True, it should be noted that there are also substandard sensors on sale, which, when installed on the engine, will also not work.
If, after removing the connector from the sensor, the fan does not work, then its performance must be checked by connecting it directly to the battery. There are only two variants of the experiment. If the fan is running, then you will have to check the operation of the fuse that protects this circuit, the fan relay and the ECU. And if the fan does not work, then you will have to check the condition of its brushes for wear.
On carbureted engines car VAZ-2107, there will be no ECU in the electrical circuit for turning on the fan, and some "sevens" do not even install a relay for turning on the fan. Therefore, it is much easier to find the reason why the fan does not turn on, and many drivers of VAZ-2107 cars can handle this.
The cooling system is designed in such a way that the fan starts only after the engine has warmed up to the set temperature. A failed fan switch can cause serious engine problems.
Do not confuse this sensor with the engine coolant temperature (CTO) sensor, which displays engine temperature on the instrument panel and is installed on the right side of the engine.
You can only notice its breakdown in time, perhaps only in the summer, and even then in the city or when driving slowly, since the oncoming air flow is quite enough for the normal operation of the cooling system. The cooling system fan, on VAZ 2107 cars, starts with a characteristic noise, so the moment it starts is clearly audible.
Where is the turn-on temperature
The fan activation sensor is located for injection models, on the aluminum outlet pipe of the cylinder head (article - 23.3828, used in VAZ-2107i-2112, 21213, 2123, ALFA ROMEO, DAEWOO, FIAT, LANCIA, OPEL), on carburetor models (TM 108 -02 92/87 C) it is installed on the engine cooling radiator.
For the “classics”, the fan operation temperature is 92 degrees and the shutdown temperature is 87 C 0, therefore, installation of a suitable size, but with a different number, is not recommended.
On carbureted models, the sensor is located on the radiator
Checking the electric fan and its circuits
In order to check the operation of the fan and power circuits on the injector "seven", you need to disconnect the connector from the sensor, the ECU will give the command to turn on the fan. If this does not happen, then it is not the sensor itself that needs to be checked, but the health of the F7 fuse, the electric motor, the fan relay and the power circuits. Below is a diagram for switching on the cooling fan VAZ 2107 injector.
Scheme of switching on the cooling fan VAZ 2107 (injector)
The principle of operation of such a device differs from TM 108 and is based on a change in resistance.
When the sensor heats up, it reduces the resistance, the ECU controls this change and, when the set parameter is reached (about 195 ohms), turns on the fan relay.
On the carburetor model, everything is made somewhat simpler, if the fuse and relay are working, then in order for the electric motor to work, it is enough to remove the chips from the sensor and close them together.
The principle of operation of the fan switch-on sensor installed on the radiator is such that when cold, the bimetallic plate opens the contacts, and when the temperature reaches 92 degrees (ideally), it closes and the relay is activated. In practice, quite often you can buy sensors with a certain spread of values. You can check the new one by heating it in water, controlling the temperature and turning it on.
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Diagnostics
You can check the fan on sensor by measuring the resistance under various temperature conditions. To do this, use a tester (multimeter) in ohmmeter mode and measure the resistance of the part. It should decrease in proportion to the heating of the coolant, as already mentioned, the higher the heating, the lower the resistance.
The resistance can be checked without removing it from the machine, for this it is enough to remove the chip and take measurements on the contacts of the part and warm up the engine by controlling its heating using the instrument on the panel. See below for a table with approximate values for the dependence of resistance on temperature.
Before installing a new controller, you can check the change in resistance in a container of heated water.
You can check the electric motor by applying voltage from the battery, the blue wire is “+”, blue with black or just black is “-“.
It happens that the fan starts at unusually high temperature values, this indicates a malfunction.
If during the test it turns out that the electric motor, fuse, sensor are all OK, in this case, you need to check the health of the relay. Sometimes the contacts just burn out. In the photo below
The fan relay on the VAZ 2107 injector is located on an additional block under the "glove compartment" (see photo), it is the far left number 23-3787.
VAZ 2107 fan relay (injector)
If you have nothing to replace this relay, then you can fix it. The contact is attached to the plate and in order to restore its performance, it is enough to press the contact. For this:
It should be noted that over time, the breakdown is repeated, checked.
Sensor replacement
Replacing the sensor on an injection model is easier than on a carburetor model, since there is no need to drain the coolant. It is enough to put some kind of rag to absorb the spilled coolant. With a key of 19, the part is unscrewed, a new one is removed and quickly installed. When installing, it is rational to apply sealant to the threads in advance.
To carry out the replacement procedure on a carburetor machine, you must first drain the antifreeze (antifreeze) and only then unscrew the sensor with a 30 wrench and install a new one.
When buying sensors and temperature controllers, try to choose branded parts.
Not a single internal combustion engine can function without proper cooling, and the VAZ 2107 engine is no exception in this sense. If a problem occurs in the cooling system, then overheating of the motor is a matter of several minutes. Often the source of the problem is the fan on sensor. Fortunately, the car owner may well replace it with his own hands. Let's try to figure out how it's done.
The purpose of the VAZ 2107 fan switch-on sensor
The purpose of the sensor is easy to guess from its name. This device is responsible for the timely inclusion of a fan that blows over the main cooling radiator.
Additional airflow is required when the antifreeze in the radiator heats up to a temperature above 90 ° C and the engine stops cooling normally. As a rule, this happens in the warm season when driving around the city or on country roads.
Designs and principles of operation of sensors
Over the years, various models of fan switch sensors were installed on VAZ 2107 cars. At first, these were electromechanical sensors, then they were replaced by electronics. Let's consider each device in more detail.
Electromechanical sensor VAZ 2107
Inside the electromechanical sensor is a small container with ceresite mixed with copper powder. Above this substance is a flexible membrane with a pusher attached to it. And the pusher, in turn, is connected to a moving contact. This whole structure is housed in a steel case with thick walls (which are necessary to ensure more uniform heating of the sensor). On the outer part of the case there is a thread and a pair of electrical contacts.
The sensor is based on a simple principle: the volume of ceresite changes with increasing temperature. Ceresite, warming up under the action of almost boiled antifreeze, expands and raises the membrane, which sets the pusher in motion. It reaches the moving contact and closes it, causing the fan to turn on. When the antifreeze temperature drops due to additional blowing, the ceresite cools down, the membrane goes down, the contact opens and the fan turns off.
Electronic sensor VAZ 2107
The basis of the electronic sensor is a thermal resistor inserted into a massive steel case. As in the previous case, the case has a thread that allows you to screw the sensor into the radiator, and a pair of contacts.
The operation of an electronic sensor is based on a change in the resistance of a resistor under the influence of high temperature. Changes in electrical resistance are tracked by a special circuit. And when the resistance reaches certain values, the circuit sends a signal to the contact system, they close and turn on the fan.
Sensor location
On almost all classic VAZ models, the fan switch sensors are screwed directly into the cooling radiators. This is necessary so that most of the working surface of the sensor is in contact with hot antifreeze. Between the sensor and the radiator, a special sealing gasket made of a material resistant to high temperatures is installed without fail.
Since the VAZ 2107 fan sensor is screwed into the lower part of the main radiator, it is most convenient to change it from the inspection hole on which the car must be installed.
Checking the performance of the fan sensor VAZ 2107
To check the health of the fan on sensor on the VAZ 2107, you will need the following things:
- a container for boiling water;
- thermometer;
- household boiler;
- fan switch removed from the machine;
- household multimeter.
Sensor Test Sequence
The sensor check sequence is as follows:
Video: checking the health of the VAZ 2107 fan sensor
Malfunctions associated with the VAZ 2107 fan sensor
There are a number of the most common problems due to which the fan on the VAZ 2107 may not turn on at the right time, which will lead to engine overheating. Here they are:
Replacing the fan switch sensor VAZ 2107
Fan sensors on the VAZ 2107 cannot be repaired. There are simply no parts that a car owner could buy and replace on their own. In addition, the sensor housing is monolithic and non-separable, so it is impossible to get to the insides of the sensor without breaking it. Therefore, the only thing that a car owner can do if the fan sensor breaks down is to replace it. The following tools and consumables are required to replace the sensor:
- an empty container of 8 liters for draining the coolant;
- open-end wrench for 30;
- 8 liters of new coolant;
- new fan switch.
Operating procedure
When replacing the fan on sensor with a VAZ 2107, proceed as follows:
- The car is installed above the viewing hole. The plug is unscrewed in the radiator, the antifreeze is drained into the prepared container.
- With an open-end wrench for 11, both terminals are removed from the battery.
- Contacts with wires are removed from the fan on sensor. This is done manually, just pull the wires towards you.
- The sensor is unscrewed with an open-end wrench by 30 (it should be remembered that there is a thin sealing ring under it, which is easily lost).
- The unscrewed sensor is replaced by a new one (when screwing in a new sensor, do not use too much force, since the thread in the sensor socket is very easy to break).
Video: replacing the fan switch sensor
So, the procedure for replacing a fan sensor with a VAZ 2107 is not particularly difficult even for a novice motorist. If you follow the above instructions, you can save about 600 rubles. This is how much it costs to replace the sensor in a car service.
Most VAZ-2107 car owners faced the problem of engine overheating due to untimely turning on of the radiator fan. Such a malfunction poses a serious threat not only to the cooling system, but to the entire power unit. An increase in coolant temperature to critical levels can damage the valve cover, as well as cause jamming of the moving parts of the motor.
Most often, the radiator fan does not work due to problems with the sensor for turning it on. This can be either a banal lack of contact on the connectors, or the failure of the device as a whole. In this article, we will talk about what measures can be taken if the fan switch-on sensor on the VAZ-2107 has lost its functionality, and we will also consider the process of checking and replacing it.
Engine Overheating Signs and Precautions
If you, while driving, find that the needle on the coolant temperature gauge has moved into the red sector and continues to deviate in the direction of its increase, it will be better to stop on the side of the road and immediately turn off the engine. If this is not done, the antifreeze or antifreeze will simply boil and try to break out, violating the tightness of the system. It is quite dangerous to continue driving in such a situation. Having stopped, it is necessary to check the performance of all elements and establish the cause of overheating. Further, if possible, it must be eliminated. And if this is not possible, tow the car to the nearest service station.
What's wrong with the fan?
If you suspect a faulty cooling radiator fan of overheating, first of all check it for operability. It is quite easy to do this. Disconnect the electrical connector from the electric motor, and bring electricity from the battery to its contacts. Do not reverse the polarity!
If the fan does not work when connected directly, the cause must be sought in the electric drive. If the electric motor has started, the problem most likely lies in the elements that ensure its inclusion. It can be a fuse, relay, wiring and sensor.
Further verification
Further verification should be carried out according to the scheme "from simple to complex". Diagnosing wiring without the appropriate tools and skills is almost impossible. The situation is similar with the relay. It is unlikely that it will be possible to check it yourself, especially in the field. The only thing that can be done is to remove a similar device from a nearby socket or another car and insert it into the appropriate socket. Has earned - the reason is established, the fan does not work - we go further.
There will be no problem with checking the fuse. We find the desired insert in the mounting block, check it with an ordinary tester or a home-made probe made of two wires and a lamp, and the result is obvious. If necessary, change the fuse and continue driving. But if this time we were wrong, the problem must be sought in the fan switch-on sensor.
Features of the cooling system in different versions
Before proceeding with the diagnosis of the sensor, it must be found. The fact is that in carburetor "sevens" and in cars with controlled fuel injection, it is located in different places. Moreover, VAZ-2107 injection machines do not have a fan switch-on sensor as such. It performs its functions. Let us consider in more detail the location of these devices in carburetor and injection "sevens".
For all outdated modifications of the "classics", the sensor is located on the body of the cooling radiator. To be precise, it's on the bottom right. Outside, it looks like a brass nut on "30" with two pins out. Raise the hood, look at the back of the radiator - you will definitely see it. The principle of operation of the sensor is very simple. The thermocouple reacts to the temperature rise, closes the contact, and the fan is energized. For cars with controlled fuel injection, the fan turns on at the command of the electronic unit based on data received from the sensor. In other words, the ECU itself controls all processes. But where is the fan switch on sensor for injection "sevens"?
As already mentioned, they do not have such a device at all. Don't look for it on the radiator or anywhere else! But look at the thermostat. A coolant temperature sensor is installed on its body. He then transmits to the electronic control unit all the necessary information about the coolant temperature.
Sensor test
Now let's talk about turning on the fan (VAZ-2107). And let's start with the carburetor engine. Everything is very simple here. All you have to do is disconnect the wires from the sensor. To do this, remove the electrical connector from its terminals. To determine if the device is working, turn on the ignition and close the contacts on the connector. If it's all about the sensor, the fan will definitely turn on.
It may also happen that the fan switch does not react correctly to the temperature. In other words, the contact closure mechanism works, but at a higher value. So, for VAZ-2107 carburetor machines, the fan switch-on sensor should close the circuit when the coolant reaches a temperature of 92 degrees, and open it at 87 ºС.
For engines with variable fuel injection, the verification process is slightly different. Since the VAZ-2107 injection cars do not have a fan switch-on sensor, you need to check it. But first you need to inspect the presence of voltage at the connector contacts. Take the tester and turn it on in voltmeter mode. Connect the negative wire of the device to ground, and connect the positive wire to terminal "A" on the connector. Turn on the ignition. The tester should show a voltage of at least 12V. If its value is reduced, the problem must be sought in the control unit. But if everything is in order with the voltage, unscrew the temperature controller from the nozzle for further verification.
Checking the sensor is to measure its electrical resistance at different temperatures. Switch the tester to ohmmeter mode and measure the resistance at its contacts. It is noteworthy that it grows and falls in inverse proportion to the temperature of the coolant (20 ºС - 3.5 kOhm; 40 ºС - 1.5 kOhm; 80 ºС - 340 Ohm; 90 ºС - 250 Ohm). During resistance measurement, the controller can be heated by placing it in a container of hot water. The temperature of the fan switch on sensor (VAZ-2107, injector) for different versions of ECU firmware can be 92-95 ºС. Its resistance is close to zero.
It should be noted that the fan activation and coolant temperature sensors cannot be repaired. Therefore, if the slightest malfunction is detected, they must be replaced. Consider the replacement process for each of the engines separately.
The process of replacing the sensor on a carburetor engine
This is where the process may seem more complicated. Indeed, given that the sensor is located at the bottom, you will have to drain the coolant. And for this you need to look for a viewing hole, remove the engine protection, etc. But you can not do this. It is enough just to quickly wrap the new sensor in place of the old one. Naturally, a little coolant will spill out, but its amount will be limited to 20-30 ml. In addition, you can always substitute a properly cut plastic bottle under the junction.
So, prepare a new sensor and a wrench on "30". Disconnect the wires from the device. Carefully unscrew the sensor with a wrench. Continue unscrewing it by hand, pressing it against the radiator housing. When the sensor comes off the thread, you can pinch the hole with your finger, and start screwing in a new element with your other hand. Do not manage to lose the sealing ring that is put on the threaded part of the device. That, in fact, is the whole process. It remains to connect the wires to it, start the power unit and check if everything works.
Replacing the fan switch sensor: VAZ-2107 (injector)
In an injection engine, coolant drain is not required to replace the sensor. It is located high enough, so its leakage will be minimal. Replacement will require a new temperature sensor and a key to "19". First, disconnect the connector, then unscrew the old controller and screw in its place a known good one. Connect the power and start the engine. If everything is done correctly, the operation of the fan is guaranteed.
Before turning off the power to the sensors, especially on the "sevens" with injection motors, it is recommended to remove the negative terminal from the battery. When choosing sensors for turning on a fan or coolant temperature, it is better to give preference to branded factory products. After replacement, do not forget to check the tightness of the threaded connection. If necessary, use a heat-resistant automotive sealant.
This article will talk in detail about the forced fan VAZ 2107. Two types of this design can be distinguished - electrical and mechanical. Any owner of the seven begins to regret that in the summer in a traffic jam, the fan switch sensor suddenly fails. After such a case, as a rule, they begin to think about improving the design. And there are several ways to upgrade.
Method one - mechanical type forced cooling
Perhaps you can call it that. Remember the first VAZ 2101-2107 cars that did not use electric fans. In them, the radiator was blown by an impeller screwed to the pump rotor. The exact same fan can be installed on the VAZ 2107 injector. The design of the cooling system is not much different.
But it is necessary to immediately say about some features of this design. The fact is that even in winter the radiator will be blown by air flow. This lowers the temperature of the engine, so the cabin can be quite cool. In the summer it’s good - the motor is always cooled, the fan is constantly running, the antifreeze does not boil.
But make two more small improvements and summer operation will be just a fairy tale:
- Place a plastic diffuser that will direct the air beam into the radiator cells.
- The upper part of the radiator must be installed a little closer to the impeller blades. Make fasteners with small strips of hard metal. Try to make sure that the distance from the surface of the radiator to the impeller is in the range of 2-4 cm.
These are the little tricks that will help you improve the cooling of the VAZ 2107 engine. The price of the issue is literally miserable - no more than 80 rubles (that's how much the impeller costs).
Method two - electric
If you have a new car, an injector and an electric fan, is it worth spoiling it with a forced impeller? It would be somewhat wiser to leave the electric fan, but make a backup way to turn it on using the button. In the store, purchase several items and materials:
- New sensor (if the old one has become unusable).
- Electromagnetic relay with normally open contacts.
- Red wire with a cross section of 0.75 square meters. mm.
- A button for installation in the dashboard of the VAZ 2107 (preferably with backlight).
- Heat shrink insulation.
- Female connectors and relay socket.
The connection diagram is shown in the photo. First of all, turn off the fan and change the sensor for turning it on. Then assemble the diagram.
Please note that newer vehicles use sensors capable of switching very high currents. But despite this, they still burn out. Sudden loads still quickly disable it. What to do? There is only one way out - to reduce the current at the sensor outputs. To do this, introduce an electromagnetic relay into the circuit. Now the chance of sensor failure is reduced. But the chance of failure of the relay becomes higher. True, it will be easier to change it.
You install a button for forced turning on the fan in the dashboard and extend two wires from it - one can be connected immediately to the "ground", and the second - to the sensor output. It turns out that you have the contacts of the button and the sensor connected in parallel. Therefore, if the sensor fails, you can turn on the electromagnetic relay with the button.
Method three - perfect fans
To improve the cooling of the VAZ 2107, you can use more modern ones instead of a standard electric fan. Those that are put on cars of the Kalina and Priora models are perfect. An electric fan with eight blades will work especially well. The air flow from it will be much stronger, therefore, the radiator cells will cool faster.
You can even get carried away with the issue of improving cooling and install two such fans. But does it make sense. It’s better then to completely clean the cooling system from the inside, replace all pipes, install a pump with an improved impeller. And finally change the radiator. This will be much more efficient than making a huge "collective farm" around the radiator.
