To maintain the engine temperature, the VAZ 2110 cooling fan switching circuit is used. Switching the fan motor on and off is controlled automatically.

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, TM-108 is used for this, and on cars with an injection engine, the control is carried out by a controller.

When controlling the fan, whether it is turned on depends on the temperature setting of the sensor, which is indicated on the case. If the fan does not turn on when the temperature rises to the sensor response temperature, you must first check the serviceability of the sensor. To check, just close the contacts on the sensor and if it turns on, you need to change the sensor. If after closing the terminals the fan does not work, then the cooling fan switching circuit and the integrity of the fuse need to be checked.

Circuit diagram for switching on the cooling fan for a VAZ 2110 injection engine.

The circuit for switching on the cooling fan of a VAZ 2110 with an injection engine is powered by an electronic engine control controller. The response temperature in this case is set in the controller program and can be from 100 to 105 degrees. C. If the temperature sensor malfunctions, an error code is entered into the controller’s memory, and the fan turns on while the engine is running.

The fan does not turn on.

But there are malfunctions in which the controller does not recognize the malfunction and the fan may not turn on when the temperature reaches above 105 degrees. C. In this case, to check the circuit and sensor, it is necessary to remove the connector from the temperature sensor with the engine running. If the circuit is working properly and the sensor is malfunctioning, the fan will turn on and turn off when the connector is returned to its place.

If the circuit malfunctions, it is necessary to check the integrity of the fuse, the serviceability of the relay and wires, according to the circuit. For a quick check, you need to bridge terminals 30 and 87 of the fan relay, located in the heater shaft on the passenger side. If the fan works, without removing the relay from the block, connect the case and pin 86 of the relay with a test lamp, the relay should work and the fan should turn on. In this case, the controller or the wire connecting the relay to pin 46 of the controller is faulty.

If you do not hear the characteristic click of the relay turning on, and a positive signal is supplied from the main relay to pin 85 of the relay, and if there is a click and the fan does not turn on, change the relay. When installing a jumper between pins 30 and 87 does not turn on the fan, check the integrity of the fuse and the presence of power at the fan terminals. If there is power on one terminal and no power on the other, this indicates a possible malfunction of the fan motor.

Instructions

Cars use electric fans to blow air over the radiator of the cooling system. The fan is a DC impeller mounted in a round or square frame. The activation of the electric fan is fully automatic and depends on the temperature of the coolant in the radiator. Fluid temperature data is taken from a sensor installed in the side compartment of the radiator. The sensor is a simple microswitch whose contacts are normally open. They close when a certain temperature is reached.

To connect an electric fan, you can use two circuits: relay and relayless. The difference between these schemes is clear from the name. The relayless one consists of a temperature sensor, fan, fuse, and connecting wires. The positive terminal of the electric fan is connected through a fuse to the positive terminal of the battery. The negative terminal of the fan is connected to any terminal of the temperature sensor; the polarity of the connection does not matter. The second terminal of the sensor must be connected to the car body. This is the simplest switching scheme and does not require much time to implement.

The relay circuit contains an electromechanical relay. The good thing is that the high current is removed from the sensor to the relay. The positive terminal of the fan is connected through a fuse to the battery, the negative terminal to the body. The negative wire must be cut and the resulting two wires connected to the normally open contacts of the relay. By default, our fan is turned off. One terminal of the relay coil must be powered from the battery positive through a fuse, or from the ignition switch. The second output of the coil should be applied to the first contact of the temperature sensor, and a wire connected to the body should be mounted from the second contact. Check in advance to see if the relay has a diode connected in parallel with the coil. If available, it is important to observe the polarity of the winding power supply.

Another useful one for the fan switching circuit is the button installed in the car interior. The temperature sensor can fail at the most inopportune moment, so the button will be useful in emergency situations. Both when using the first scheme and when using the second, you need to connect the normally open contacts of the button to the temperature sensor. It’s easier this way, but if you use the first scheme, it turns out that there will be a large current on the button, and this can cause the button contacts to burn and the case to melt. Therefore, it is best to use the button in combination with an electromagnetic relay.

Maintaining normal engine operating temperature is very important to maintain engine performance. The cartoon arrow on the instrument panel, of course, shows the temperature not at all accurately and gives, rather, approximate indicators. The electronic engine control system of the VAZ-2110 with any injection engine uses completely different data, more accurate. They affect the operating temperature and the frequency of turning on the cooling fan.

When does the radiator fan turn on on a VAZ-2110

To really understand how to change the fan switching temperature on a VAZ-2110 injector, you need to know exactly the factory design parameters and the principle of fan switching itself.

In carburetor engines, the fan turned on at approximately 100 degrees.

On carburetor engines 2110 of the old model, the fan was turned on using a thermobimetallic sensor. It was installed directly in the radiator bank and set to a certain temperature. Since the normal operating temperature of antifreeze 80-90 degrees , then the bimetallic plate closed the contacts at approximately 100-105 degrees .

In injection tens The fan starts up completely differently. There are two temperature sensors installed near the thermostat - one with one wire, the second with two. The first one is responsible only for the temperature indicator needle, so there is little demand from it. The second sensor with two wires is working. It is he who supplies the impulse to the electronic engine control unit, which then supplies power to the fan motor network.

Features of the temperature sensor

However, one must understand that a temperature sensor is a conventional converter of thermal energy into a variable electrical pulse. More precisely, when the temperature of the antifreeze changes, the resistance of the sensor changes approximately in this mode:

Now the principle of operation of the fan activation system becomes clear - the ECU receives a certain electrical impulse when the temperature reaches 110 °C (133 Ohm), and supplies power to the fan motor.

As soon as the resistance of the sensor element rises to 187 Ohms (which corresponds to 97 °C), power is removed from the fan and the engine cools down.

How to change the temperature?

Over time, more and more complaints appear about the operation of the cooling fan activation system. The most important design flaw is lack of several fan operating modes and sudden start of the fan motor . Indeed, in the summer heat the fan has to work at full strength, and this is understandable. However, most often the fan produces excessive performance, which leads to rapid cooling and frequent starts.

This leads to a current overload on the on-board network.

In addition, the starting temperature threshold is too high, so the engine often overheats . Unfortunately, you can only change the fan startup parameters by reflashing the electronic control unit or upgrading the electric motor activation system. Reflashing the ECU is carried out by a competent specialist, and it is possible to set any desired temperature for turning the fan on and off.

Basic methods

Diagram for connecting an additional fan sensor.

There are also several solutions to changing the operating modes of the fan motor. The simplest of them is installing an additional switching sensor from carburetor engines (in the diagram above). It is configured to turn on at a temperature 97-100 °C, which will be quite enough. And in order for the fan to operate in this mode at half power, a resistance from the VAZ heater is installed in the circuit.

Thus, the upgraded fan will have several advantages:

1. The fan switch-on temperature is below standard.
2. Two operating modes - ½ and full power.
3. Less noisy fan operation.
4. More flexible temperature regime of engine operation.
5. The normal mode of turning on the fan is maintained.

In this way, it is possible to modify the control system for the electric cooling radiator fan of the VAZ-2110. Stable temperatures to everyone and good roads!

Video about forced fan activation

The design and circuit diagram of the radiator fan may differ not only depending on the make of the car, but also on the year of manufacture and model configuration. Let's consider not only the principle of operation, but also the connection option with the possibility of forced activation of the cooling system fan (VSO).

Cooling system design features

Depending on the design features, the fan can be turned on in 3 ways:

• using a power sensor for activation of the VSO. This sensor is also called a fan temperature relay, since the power contacts of the electric motor pass directly through the sensor. With this scheme, the load on the thermal relay increases significantly, which reduces its service life;
• using the fan switch sensor, but now closing the contacts in the temperature switch triggers the relay, through which the power contacts of the cooling fan are connected. This connection method is much more reliable than the previous option;
• using an electronic engine control unit. The ECU, focusing on the coolant temperature sensor installed in the engine cooling radiator, supplies power to the VCO through a relay. A resistive temperature sensor is used as a meter. It is this switching circuit that is used on the vast majority of modern cars. On cars equipped with air conditioning, one of the electric fans will be controlled by the comfort unit. This is necessary for forced cooling of the condenser when the interior air conditioning system is activated.

Operating modes

When understanding the operating principle and connection diagram of a radiator fan, you should remember that electric motors often have two speed modes. This is implemented in 2 ways:

• by adding a resistor to the circuit, which increases the resistance and, as a result, reduces the current. The design uses a two-contact sensor, which, depending on the temperature, powers the electric motor directly or through resistors;
• a combination of parallel and series connection. The circuit is used on a car with two fans. They can be connected in series, in which case, according to Ohm's law, they will operate from 6 V, or in series, when 12 V is supplied to each of the VSOs. The modes correspond to low and high speed rotation of the propeller.

Scheme options

Schematic diagram of VSO connection on VAZ 2108, 2109, 21099 (until 1998).

As we can see, the sensor controls the fan relay, which is located in the fuse box. When a certain temperature is reached, the contacts of the temperature switch close, which leads to the flow of current in the electric motor circuit.

Above is a diagram for VAZ 2108, 2109, 21099 cars, but after 1998. As we can see, the power sensor now functions as a relay.

Let's consider a circuit using a resistor to implement two propeller rotation speeds using the VW Passat as an example. The two-position fan power sensor S23, depending on the coolant temperature, closes the contacts directly or through an additional resistance.

DIY connection

Some drivers, warning the engine against malfunction of the radiator fan power supply thermal relay, make a remote button to force the electric motor to turn on. To do this, it is enough to connect a fixed button in parallel to the control output of the relay coming from the sensor, which, when pressed, will close the contact to ground, thereby provoking the operation of the relay. If the car's design does not provide a fan relay, you will have to install it yourself to force cool the radiator.

Under no circumstances should you connect the electric motor directly through the button in the cabin! We also do not recommend connecting the circuit so that after turning on the ignition the electric fan constantly rotates, as this significantly reduces its service life.

To connect, you only need to understand the operating principle of a 4-pin relay and minimal knowledge in installing additional equipment. Be sure to include a fuse of the required rating in the power circuit and place it as close to the power source as possible (read more).

If desired, you can replace the single-position sensor with a two-position one, which, paired with a selected resistor, will allow you to realize a low speed of operation of the VSO. If you have a sufficient level of knowledge in electrical engineering, then you can build a PWM controller to adjust the speed of rotation of the propeller. Controlling the electric fan using a PWM signal will allow you to smoothly regulate and arbitrarily select the rotation speed depending on the temperature load on the engine. There is enough material on the Internet on how to make a PWM controller with your own hands.

Many people have noticed that the temperature at which the radiator fan on a VAZ turns on is too high when compared with the operating temperature of the engine. Manufacturers are trying to reduce the amount of harmful emissions, since at high temperatures the fuel burns better together with the components.

But there is not only a positive effect, but also a negative one. If the engine overheats a little, then destructive processes begin for the metal inside, so wear resistance decreases. If you do not take into account that electrical components that affect the switched on fan may fail, then the time to notice overheating will be less than at normal temperatures.

We need to ensure that the engine operates evenly. This can be accomplished by creating a parallel fan circuit. A positive wire must be connected to one contact, and the negative contact is connected to the switch via a parallel wire.

It is worth mentioning additional features that allow you to control the normal engine temperature. There are no relays in the electrical circuit as a simple switch is sufficient for operation.

This method is not a replacement for the standard fan operation circuit, but only an alternative option for operating the unit at low temperatures. The driver must control the entire process.

If the car’s engine overheats, but this connection diagram is implemented, then it is better to check the cooling system again, ensuring its operation.

As soon as signs of overheating are detected, that is, the arrow indicating the temperature has entered the red zone, but there is still no puff of steam from the engine compartment, then turn on the interior heater at full power.

This will help reduce the temperature of the coolant in the cooling system. Next you need to turn on the emergency lights, depress the clutch pedal and roll to the side of the road. The car cannot be turned off immediately; the engine is run at normal idle speed for about five minutes, and the heater must still operate at full power. Only now can you open the hood and inspect the engine compartment.

You need to try to determine where the steam is coming from, see if there is coolant in the expansion tank, check the integrity of the thermostat, radiator and rubber hoses.