Which sensor turns on the fan? Fan switch sensor

In order to save money and simplify the design, cars use a simplified switching on of the cooling system fan. The circuit includes a fan, a fuse, a temperature sensor and connecting wires. The electric motor is connected to ground, as well as to the battery positive through a fuse. A temperature sensor is connected to the ground wire break.

This circuit is good for its simplicity; there is no need to use expensive elements, and the number of wires is minimal. But it also has its disadvantages. For example, a temperature sensor that acts as a switch passes a large current through itself, which affects its service life. And another minus is the sudden start of the engine. The load on the engine increases sharply to its maximum value, and this negatively affects the condition of the electric motor.

Using an electromagnetic relay

Using a simple relay will slightly complicate the circuit, but will relieve the temperature sensor from the presence of high current. A large current will flow through the relay contacts. It is cheaper and easier to replace the relay than the temperature sensor to turn on the electric fan. To carry out the upgrade, you will need a wire and a relay with a bracket for mounting to the body.

Disconnect the temperature sensor, and the wires that were on it must be connected to the normally open pair of contacts of our relay. Half the job is done, the power part is ready. Now control. We connect one terminal of the temperature sensor to ground, but connect the second to the relay coil.

From the second terminal of the coil you need to stretch the wire to the positive terminal of the battery. It is advisable that the connection be made through a fuse, the operating current of which can be 1 Ampere. The coil consumes a small amount of current, so the worst thing that can happen is a short circuit in the wiring. Subsequently, you can connect a forced activation button in parallel with the temperature sensor, which you will install in the car interior.

Semiconductor Applications

Instead of an electromagnetic relay, you can use a thyristor switch, or a field design. The essence is the same, only there are no moving contacts; their functions are performed by electrons and holes in the semiconductor crystal. But do not forget about cooling the thyristors and install radiators that will be able to provide the necessary heat transfer.

Smooth engine start is very useful feature for engine control. This innovation will ensure a gradual increase in load. This idea is accomplished by using PWM modulation. But along with all the innovations, you can use a second temperature sensor in the cooling system, whose response temperature is 5 degrees lower than the main one.

If, when the main sensor is triggered, the fan turns on at full power, then when the second sensor is triggered, its speed should be half as much. To do this, you will have to use a resistor when connecting. The one installed on the stove fan is perfect. This will prevent the temperature in the system from reaching extreme values.

Many owners of VAZ family cars often encounter the problem of engine overheating. This disease occurs for various reasons, but one of the most common problems is the untimely activation of the radiator fan. Such a malfunction can lead to serious damage. Not only does the valve cover fail, but the power unit may also become jammed.

To protect your car from breakdowns and ensure uninterrupted engine operation, you need to monitor the condition of all the main sensors of the system. How to check the fan switch sensor for functionality?

On all VAZ cars with a carburetor engine, the fan switch sensor is located on the radiator housing. That is, to find this device, just open the hood and find a mechanism similar to a nut with contacts on the side of the cooling radiator.

Heating the threaded part directly in the coolant leads to the closure of the contacts. In turn, the voltage from the battery is supplied to the electric motor, which drives the fan.

Sensor check

While driving on high speed The engine cools naturally. In hot weather and at low speeds, the motor may overheat. An increase in the instrument panel temperature may indicate that the sensor has failed. The device comes into operation when the coolant temperature reaches high values.

To diagnose it, it is absolutely not necessary to go to a service station. It is enough to arm yourself with a handy tool and do the following work:

• Check the fuse for operability; if it fails, then install a new one;
• Close the contacts of the mechanism; if the fan starts working, then most likely the switch on sensor needs to be replaced;
• Check the wiring, which in most cases is the cause of lack of power and ground faults.

There is also an alternative way to check the functionality of the mechanism using . To do this, you need a container with liquid and a heat source. The first step is to disconnect all electrical connectors of the sensor and unscrew the mechanism with a key. You should first drain the antifreeze and do the work on a cold engine. The principle of checking the serviceability of the DVV is similar to checking the thermostat.

The multimeter terminals are connected to the contacts of the thermal switch and the device is switched to the “ringing” operating mode. The fan sensor is placed in a container of water with the threaded part. Then the heat source is turned on and the water is heated. The temperature range for turning on the mechanism is usually displayed on the device body. This is often between 85 and 92 degrees. When the water is heated to these values, the sensor should make a sound characteristic of its activation. If nothing happens, then the failed mechanism should be replaced.

Self-replacement of internal combustion engines

Replacing a broken device begins with removing the battery terminals. Then you need to drain the coolant from the system and unscrew the device from the radiator housing. Assembly is carried out in reverse order. The work will not take much time even for a novice driver. To improve the cooling system, it is possible to install a fan from Niva.

Injection modifications do not require draining the coolant. To replace the sensor on a VAZ-2107, VAZ-2109 with an injector, it is enough to have a key on hand to “19” and unscrew the mechanism. Install a working device in its place.

When choosing a new sensor, it is best to pay attention to branded, factory-made devices that have the appropriate certificates. On the market today you can easily stumble upon cheap fakes.

After replacement, all connections should be checked for leaks. It is also important to constantly monitor the engine temperature, since the driver has only a few minutes to prevent serious consequences from high temperatures in the main unit of the car.

With change mechanical drive An electric fan came, and with it a sensor for turning on the VAZ fan. He performs to the utmost simple function– when the engine temperature rises above the limit, it turns on the electric fan. However, if it fails, the consequences may not be very pleasant.

Installing this sensor has several advantages:

• faster engine warm-up at low temperatures;
• reduction of operating time at inefficient temperature conditions;
• more optimal fuel consumption.

Fan operation is completely unnecessary when driving at high speed, because cooling occurs naturally. At the same time, on a hot day under limited speed conditions, for example, when a traffic jam occurs, the engine quickly overheats, and a cooling fan switch is simply necessary. Typically this element is mounted on the lower pipe coming out of the radiator. The device should operate when the coolant temperature rises.

Of the entire cooling system, it is the bimetallic thermal switch that most often fails, creating the risk of engine overheating. This entails serious consequences, including jamming. In order to prevent this, you need to constantly monitor the temperature on the dashboard. You have no more than 5-10 minutes to react and turn off the engine.

Checking the functionality of the sensor

If the temperature indicator stubbornly creeps up, most likely the sensor has failed. You don't have to go to the station right away to check. maintenance. The question of how to check the fan switch sensor can be answered by performing a very simple test:

• Firstly, it is worth checking the fuse that controls the operation of the fan. If it burns out, then you just need to install a new one and not waste money on a bimetallic thermal switch.
• Secondly, you can close 2 contacts of the device; if the electric fan starts working, most likely the problem has been found and a new sensor is needed.
• Thirdly, it doesn't hurt to check the wiring. There are often cases when there was simply no power or there was a breakdown to ground.

Another way is to use a multimeter. To carry it out you will need a container of water, relatively small sizes, as well as a heat source that will heat the liquid. The principle of this method almost completely repeats the thermostat test.

The multimeter terminals must be connected to the contacts of the bimetallic thermal switch and the device must be turned on in the so-called “ringing” mode or measuring the resistance value. Next, the radiator fan switch sensor should be placed in water with the part on which the thread is located.

You can turn on the heat source and wait for the water to heat up. As soon as the thermometer shows a temperature of 92-95°C, the multimeter will make a characteristic sound. If this does not happen, the non-working element must be replaced.

Replacing the bimetallic thermal switch

Provides all the main electrical circuits and modifications for connecting the liquid cooling fan (CO) in VAZ cars various models. What is the essence of VO’s work? Electric motor with an impeller on a shaft, installed inside a rectangular metal frame, with which it is attached to the back of the radiator. When voltage (12 V) is applied to the contacts of the drive, it begins to work, rotating the blades and creating a directed stream of air, which, in fact, cools the antifreeze or antifreeze.

If the cooling fan does not work, do not rush to contact a car service. You can determine the cause of the malfunction yourself. Moreover, for this it is not at all necessary to have special skills - just study the reference material from website and follow the instructions to check/replace it.

Connection diagram for the VAZ 2104, 2105 and 2107 cooler

1. radiator fan
2. temperature sensor (located on the bottom of the radiator)
3. mounting block
4. ignition relay
5. ignition switch

A - to contact “30” of the generator.

Electric cooling fan VAZ 2106

1. electric motor switch sensor;
2. fan motor;
3. motor start relay;
4. main fuse box;
5. ignition switch;
6. additional fuse box;
7. generator;
8. rechargeable battery.

Fan connection 2108, 2109, 21099

Until 1998, on cars with the old mounting fuse block 17.3722 (finger type fuses), relay 113.3747 was included in the fan circuit. After 1998 there is no such relay.

Also, before 1998, the TM-108 switching sensor was used (the closing temperature of its contacts is 99±3ºС, the opening temperature is 94±3ºС), after 1998 the TM-108-10 with similar temperature ranges or its analogues different manufacturers. The TM-108 sensor only works in conjunction with a relay; the TM-108-10, reinforced for high current, can work both with and without a relay.

Scheme for switching on the engine cooling fan on a VAZ 2109 with mounting block 17.3722

1. Fan motor
2. Motor start sensor
3. Mounting block
4. Ignition switch

K9 - Relay for turning on the fan motor. A - To terminal “30” of the generator

Scheme for switching on the engine cooling fan on a VAZ 2109 with mounting block 2114-3722010-60

1. Fan motor
2. Sensor 66.3710 for turning on the electric motor
3. Mounting block

A - To terminal “30” of the generator

Connection diagram for VO VAZ 2110

The circuit diagram for switching on the cooling fan of the VAZ 2110 on carburetor and injection cars is different. On cars with a carburetor engine, a TM-108 thermobimetallic sensor is used for this, and on cars with an injection engine, control is carried out by a controller.

Diagram for 2113, 2114, 2115 injector and carburetor

Where is the fan relay located?

4 – electric fan relay;
5 – electric fuel pump relay;
6 – main relay (ignition relay).

Attention: the order of the relays and fuses can be arbitrary, we are guided by the color of the wires. Therefore, we find a relay from which comes a thin pink with a black stripe wire coming from the main relay (pin 85*) (not to be confused with the thin, red with a black stripe wire coming from the controller) and a thick power white with a black stripe wire (pin 87) (white and pink wires we need), this is the fan relay.

If the cooling fan does not work

An electric motor is installed to drive the fan DC with excitation from permanent magnets ME-272 or similar. Technical data of the electric fan and fan switch sensor:

• Rated rotation speed of the electric motor shaft with impeller, 2500 – 2800 rpm.
• Electric motor current consumption, 14 A
• Sensor contact closure temperature, 82±2 degrees.
• Sensor contact opening temperature, 87±2 degrees.

The cooling system fan may not turn on due to:

• electric drive malfunctions;
• blown fuse;
• faulty thermostat;
• a failed thermal sensor for turning on the cooler;
• faulty VO relay;
• broken electrical wiring;
• faulty expansion tank plug.

To check the VAZ fan motor itself, we apply a voltage of 12 V to its terminals from battery- a working motor will start working. If the problem is with the fan, you can try to repair it. The problem is usually the brushes or bearings. But it happens that the electric motor fails due to a short circuit or break in the windings. In such cases, it is better to replace the entire drive.

The BO fuse is located in the mounting block of the car's engine compartment and is designated F7 (20 A). The test is carried out using a car tester turned on in probe mode.

1. In a car with a carburetor engine you need to check the sensor - turn on the ignition and short-circuit the two wires going to the sensor. The fan should turn on. If this does not happen, the problem is definitely not with the sensor.
2. For injection cars it is necessary to warm up the engine until operating temperature, and disconnect the sensor connector, disconnecting it from the vehicle’s on-board network. In this case, the controller must start the fan in emergency mode. The electronic unit perceives this as a failure in the cooling system and forces the fan drive to operate in constant mode. If the drive starts, the sensor is faulty.

Replacing an electric fan in a car

1. We park the car on flat surface, immobilize it with the parking brake.
2. Open the hood and disconnect the negative terminal.
3. Using a 10mm wrench, unscrew the housing fasteners air filter.
4. Using a screwdriver, loosen the air duct clamp on the air flow sensor and remove the corrugation.
5. We unscrew the screws securing the cover of the air filter housing and remove the filter element.
6. Using a size 8 wrench, unscrew the air intake mount and remove it.
7. Using a 10mm wrench, then an 8mm wrench, unscrew the nuts securing the fan casing around the perimeter (6 pieces in total).
8. Disconnect the wire block on the fan connector.
9. Carefully remove the fan casing along with the drive.
10. Using a 10mm wrench, unscrew the 3 bolts holding the electric motor to the casing.
11. We put a new one in its place.
12. We install the structure in place, fix it, and connect the connector.
13. We carry out further installation in the reverse order.

Control circuit modernization

The cooling fan on the top ten turns on at a temperature of 100-105°C, whereas normal operating
The engine temperature is 85-90°C, so the fan turns on when the engine overheats, which naturally has a negative effect.

This problem can be solved in two ways: adjust the switch-on temperature in the “brains” or make a button. We'll focus on the second one. Turning on the fan from the button is very convenient: if you get into a traffic jam - turn it on, leave - turn it off, and no overheating.

A button for selecting the fan operating mode was installed in the cabin (always off, constantly on, automatically turned on via a sensor) - this “tuning” is not mandatory, but will be a very useful addition.

There will be a large current at relay contacts 87, 30, on the wire from the battery to the fuse and the fan ground, and therefore we must use wires there with a cross-section of at least 2 mm, otherwise the thinner wire will not withstand it and will burn out.

Video - connecting and checking VO

When operating a vehicle, it is important to pay attention to the temperature balance of its engine. Overheating can cause a variety of damages that require repairs and associated costs. Uninterrupted cooling operation will allow you to avoid possible troubles, where important function performs a fan activation sensor.

Functions.

The element performs the function of a thermostat, but its main purpose is to protect the vehicle’s power unit from excessive heating. When the heating reaches a certain level, you need to send a signal to the ECU to turn on the ventilation device.

How does this system work? A significant amount of generated energy is transferred to the coolant. During this process, its gradual warming up becomes inevitable. The liquid heats up significantly; after reaching t ° critical for the engine condition, the thermoelement sends a command to the electronic unit of the vehicle.

This will start the cooling process. Powerful air currents will go to the radiator. The coolant will quickly return to normal.

Where is it located?

It is important to regularly inspect the machine, paying attention to the condition of the temperature sensor. It is not difficult to detect, since it is fixed in the radiator. It is impossible to indicate a more specific location; there is variability depending on the car make, model, and year of production of the car. For example, the element is sometimes built into the left or right compartment of the radiator tank, top or bottom.

You can identify it in the radiator without much difficulty, since it is the only element to which the wires are connected.

A nut with a large head, which can be unscrewed using a 30mm wrench, will also help to distinguish.

On what principle does it operate, triggering conditions.

The temperature sensor has a relatively simple design, one of the main elements of which is a contact group located in the internal part of the assembly. When t° reaches a given limit, the contact elements expand under the influence of heat and come into contact.

The electrical signal is then sent to the ECU, and from there it goes to the fan.

Inspection and troubleshooting.

The blades of the ventilation device start after warming up to a certain value. This does not happen in two cases: the air blower is broken (it should be tested and replaced), or the fan fails.

To identify the cause of the malfunction, do the following:

• Make the sensitive thermocouple work by closing the contacts manually. When starting up the blades will need to be replaced.
• Check the fuse for continuity. It is included in the power circuit. You may not have to take your car for repairs or spend money on inspection. It is enough to replace the fuse.
• Make sure the wiring is intact.

If the listed breakdowns are not detected, you should check the temperature sensor; most likely, the problem is there.

How to check the fan switch sensor?

To check for functionality, follow these instructions:

1. Prepare a container with a depth sufficient for immersion, a 100-degree thermometer, a multimeter, and wires.
2. Connect the ends of the two wires to the meter and to the thermocouple.
3. Fill the vessel.
4. Secure the element from above (you can use threads or anything else for this) so that its metal part is submerged. Make sure that the device does not touch the container; heat should be transferred only from the environment.
5. Heat gradually, monitoring the temperature values.
6. Closing will occur after reaching a certain heating level. This will mean that further operation of the tested sample is permissible.

It is necessary to achieve compliance with the parameters set at the factory. If the contacts close at a different setting or do not react at all, then there is damage and replacement is required.

Check for VAZ 2110.

Checking your own vehicle, remember that it is necessary to take into account the temperature limits that correspond to those established for your transport.

Here are the nominal data for some car productions of the Volzhsky Automobile Plant:

1. The thermoelements of the VAZ 2110 turn on at 92 °C and turn off at 87 °C. Manufacturers offer designs with other ratings, but for 2110 this option is more acceptable. During testing for this model of transport, heating should be carried out to 92°C, a working sample will work.
2. Overheating protection in the VAZ 2109 operates according to a different scheme. Already at 88°C the thermostat opens slightly and the coolant begins to move in a circle. If the temperature continues to rise and reaches 90°C, the fan starts. It starts working for cooling. The contacts close at 90°C and open in environments colder than 90°C.
3. For VAZ 2114, switching on is initiated at 102-105°C, and switching off is 85-87°C. When purchasing a new meter, choose an analogue of the failed one or focus on these values.

The declared response parameters are usually marked on the element itself.

Checking the relationship between resistance and temperature.

You can check the serviceability by using an electric kettle for heating, as well as a multimeter turned on in resistance measurement mode.

1. While the electric kettle is heating up, the working part of the sensor is immersed in cold water.
2. A multimeter is connected to the device. A thermometer capable of measuring high temperatures is immersed, after which the kettle is turned on.
3. As the temperature increases, the resistance readings on the device will decrease.
4. It is necessary to heat up to the nominal activation parameter of the temperature sensor, now the Ohm value on the multimeter should correspond to the nominal

Check without using a thermometer.

Another method allows you to take measurements without using a thermometer.

1. Heat the water until it boils. In this case, the temperature will reach 95-97 °C.
2. Note the ohm readings on the multimeter. They must correspond to the nominal boiling point. The difference is too big - the sensor must be replaced.

How to determine that the DVV needs replacement?

It is generally accepted that the design of temperature sensors is reliable due to its simplicity. But this is not entirely true. Failures can be caused by a violation of calibration, which leads to changes in resistance and causes malfunctions of the electronic unit.

When one sensor is used to regulate startup, a clear indication of its malfunction is when the fan stops working.

Modern cars are able to display information about a malfunction on the on-board computer display. However, these indicators do not always mean that it is time to replace the sensing element. The wiring may have been damaged or parts may have oxidized.

The operation of a damaged temperature sensor will soon affect the functioning of many devices: fuel consumption will increase, the idle speed will increase, and detonation will occur. It is likely that the car will become much more difficult to start after warming up, and the power plant may overheat.

Sometimes, drivers try to save money and are in a hurry to replace spare parts. Such actions can lead to even greater costs, since the failure of one part inevitably leads to the deterioration of many others. It's better to buy new spare part It is more modern than later to hastily solve even more complex problems.

Video instructions.