What is the name of the stove in the car. The principle of operation of the car oven

the main task car stove- create heat in the cabin. At -25 degrees outside, it should be +16 inside the car, this is according to GOST.

The device of the stove in the car is very simple. Heat enters the car from the engine. The pump drives the antifreeze both through the engine cooling system and through the car heating system. Hot antifreeze enters the stove radiator. He, like a battery, heats up, and the fan drives air through it, which blows directly into the cabin. After passing through the stove, the antifreeze returns to the engine.

For the first time, heated cabins appeared on american cars in 1917. Salon warmed off exhaust pipe. Soviet drivers in order not to freeze, they drilled in several places a partition between engine compartment and cabin. This saved them from frost even in severe cold.

Faulty pump, clogged stove radiator, faucet, air - these are the most common causes oven failure. Let's start with the pump.

With a faulty pump, the interior warms up 2-3 times worse than with a fully functional one. And this is not the worst. A non-working pump threatens with big troubles. Because of faulty pump can drive the cylinder head. The engine from overheating may jam and subsequently require overhaul motor.

Sometimes the stove does not heat well due to fault faulty faucet. It can become clogged or broken from old age. It's easy to check: the inlet hose at the stove radiator is hot, and the outlet is cold. Try to open the tap manually, if it doesn't work out, feel free to change it.

If, with these symptoms, you removed the faucet, but it turned out to be in order, then things are bad: the stove radiator is clogged with scale from the inside. It will have to be changed and nothing can be done about it. Outside, the enemies of the radiator are fluff, road dust, dry leaves and other dirt. With the radiator blocked, the air temperature in the cabin will rise only a few degrees, because cold air from the street does not pass through the radiator grill of the stove, but simply blows it around the edges.

The air bubble in the engine stove feels great, because the antifreeze flow in the narrow tubes of the radiator is too weak, unable to expel the plug. To get rid of it, here's a tip for you: warm up the engine, but not for long so as not to burn your hands. Loosen the clamp on the hose that goes to the stove and carefully remove it from the tube so that a small gap forms. Air will come out through it.

Quality antifreeze, control of its level, but only with a cold engine, and a clean radiator of a car stove - these are simple ones that will save you from cold and dampness in the cabin. And one more thing: do not abuse the sealants of the cooling system. Together with the slots, they also plug the radiator tubes.

With the advent of cold weather, some drivers are puzzled by the search for reasons why the stove does not heat well in the car. And sometimes the stove in the car starts to work so poorly that it becomes absolutely unable to warm the interior. Moreover, in hard frost The situation is further aggravated by the freezing of glass. What to do in such cases?

In fact, there are not many reasons why the stove in the car interior may not work efficiently, and below we will consider each of them.

At the end of this article, watch a video with a detailed description of the reasons why stoves in cars do not work well, and how to fix them.

In the meantime, you will find out the reasons why the stove does not heat well, we recommend that you pay attention to alternative ways heating in the car:

• How to choose a car interior heater from the cigarette lighter;
• How to choose a heated car seat cover.

Of course, these "warmers" will not replace the regular stove in the car, but, undoubtedly, they will add comfort even after its repair.

7 reasons why the stove in the car does not heat well

In order to better understand the reasons why the stove does not heat well in the car and understand why it does not work as it should, you need to get to know the device of the car's interior heating system better.

The stove in the car will heat well and without failures if all its components and components are in good order. The interior heater is quite simple, and in most cars it consists of the following parts:

• Heater control unit;
• Stove radiator (heat exchanger);
• Branch pipes (underwater and outlet);
• Valve for adjusting the supply of coolant (antifreeze);
• Air dampers with actuators;
• Fan;
• Air ducts.

Below we list seven main reasons why the stove in the car may heat poorly or not work at all:

1. Air in the heating system
The oven in the car will not work in normal mode in case of air ingress when replacing antifreeze in the engine cooling system. Air can also enter the heating system if the cylinder head is leaking.

2. Faulty thermostat
A car thermostat can get stuck in both the open and closed positions. If at long drive in fourth or fifth gears, the stove in the car heats up badly, and in small gears (1-3 gears) it is good, then the problem is most likely that the thermostat is stuck in the open position. If the thermostat is stuck in the closed position, then there will be no problems with the operation of the stove, but the engine will overheat, which can even lead to its failure.

3. Clogged stove radiator
The stove radiator in the car can become clogged different reasons, both outside and inside. Outside, the radiator is clogged as a result of dust, insects, leaves - everything that enters it through a protective casing. From the inside, the stove radiator becomes clogged with dirt and deposits present in the engine cooling system over time. Also, low-quality antifreeze can become the cause of "overgrowing" of the channels of the radiator pipes.

4. Clogged cabin filter
The stove in the car can also heat poorly due to heavy pollution. cabin filter. Remember to change your cabin filter at least once a year.

5. Fan failure
The fan that blows air into the passenger compartment may not work properly as a result of bearing failure or graphite brushes- this will lead to precarious work the entire ventilation and heating system. Also, the fan may not turn on due to problems in electrical circuit nutrition.

6. Malfunctions of the heater tap
Most often, such malfunctions occur in stoves. domestic cars(VAZ, GAZ, UAZ, etc.). For example, the faucet lever may work, or the rubber bands may dry out, or the lever itself will turn sour. In such cases, it is better to replace the stove tap, and preferably immediately together with the radiator.

7. Failure of the stove control unit
This malfunction also often causes trouble for owners of VAZ cars. That there are problems in the control unit (on modern cars- heater controller) indirectly indicates the poor operation of the fan in some operating modes of the stove. It can also lead to malfunctions of the unit faulty sensor air temperature in the car.

Of course, that's not all possible reasons, according to which the stove in the car can heat up badly, but they are most often found in case of problems in the car’s heating system.

If the stove in the car heats up poorly or does not work at all, then you first need to determine the cause of the malfunction, and then eliminate it. Most problems with a car stove are manifested as follows:

• The stove in the car does not heat well;
• The stove in the car blows cold air;
• The stove in the car sometimes works, sometimes it doesn’t (it blows either cold or hot air);
• The air from the stove in the car is hot enough, but it blows weakly;
• The stove in the car does not work (does not turn on).

We have summarized the possible causes in the table below. incorrect operation car interior heating systems, described how they can affect the operation of the stove, and listed ways to eliminate them.

Possible cause of oven failure	Malfunction symptoms	Solutions
Air in the interior heating and engine cooling system	1. The stove does not heat well; 3. The stove blows either cold or hot air.	1. Remove air from the system (easy way); 2. If the air is not removed or appears again, check if the cylinder head gasket is broken.
Thermostat stuck open		Check thermostat, if a malfunction is detected, replace with a new one.
Clogged heater core	1. The stove does not heat well; 2. The stove blows cold air.	1. Vacuum the surface of the radiator; 2. Flush the engine cooling system; 3. If nothing helped, replace the radiator.
Problems with the heater valve or air damper control levers		1. Check if the cable has come off the damper control levers or the heater tap; 2. If the heater tap is faulty, it must be replaced.
Clogged cabin filter	1. The air from the stove is hot enough, but it blows weakly.	Replace cabin filter.
The fan is not blowing well		Contact a specialist (auto electrician) to determine the causes of the malfunction and eliminate them.
The fan does not turn on	1. The stove in the car does not work (does not turn on); 2. The air from the stove is hot enough, but it blows weakly and only at high speed.
Problems with the stove control unit	1. The stove does not heat well; 2. The stove blows cold air; 3. The stove blows either cold or hot air; 4. The stove does not work (does not turn on).

In order for the stove in the car to warm up well and not let you down at the most inopportune moment, you need to follow a few simple tips.

1. Keep the radiator clean. Slight contamination of the radiator from the outside can be removed with a vacuum cleaner. Flushing the engine cooling system, with which the stove radiator is inextricably linked, will help get rid of internal deposits and blockages in the channels.
2. Use good antifreeze . High-quality antifreeze is the key to long-term operation of not only the stove in the car, but also the engine. Keep this in mind and do not forget to replace it in a timely manner.
3. Change your cabin filter often. clogged filter interior will certainly create problems not only for the operation of the stove, but also for the air conditioning and ventilation system of the cabin as a whole. In addition, dust and plant pollen deposited in the filter can pose a serious health hazard (especially for allergy sufferers).

If, at a temperature outside of minus 25 ° C, the stove of your car heats the interior up to +16 ° C from below and up to +10 ° C from above, then it can be considered quite serviceable. In order to avoid problems, it is recommended to take timely and responsibly preventive measures that will allow you to enjoy comfortable ride in a well warmed up car.

And remember what longer term service life of the machine, the more attention its heating system requires. This applies to all vehicles, regardless of country or manufacturer.

Video: why the stove does not heat well in the car

Today, a very relevant article (especially in winter) - the car stove does not heat up, or it heats up very badly! Why is this happening and what are the main reasons for this. After all, a normal working car should warm up the interior within 10 - 15 minutes (unless, of course, you have turbocharged engine, according to it). If after 15 minutes you can hardly go warm air(or does not go at all), and all the glasses inside are frozen, then this is not “eating well”! Read my tips below...

To begin with, let's think - how does the car warm up? As we all know, when the engine is running internal combustion gets very hot, this happens from the friction of the pistons against the cylinder walls, as well as from combustion fuel mixture. If you do not cool the motor, then it will quickly fail (the pistons will simply jam). A whole cooling system was made of pipes, tubes and radiators, which prevents the power unit from overheating. So one of the radiators is inside the cabin, under the instrument panel. If you do not go into complex technical details, then this stove radiator (warmed up by engine coolant) heats up your interior. And in order to increase the heating efficiency at times, there is a fan nearby (having several modes of operation, faster - slower) that blows this radiator, due to which warm air intensively enters the cabin (both on the windows and on the passengers). And if something disrupts this process of work, then cold air enters the cabin, that is, the stove does not heat up. Now let's talk, in fact, about the main reasons

There are about five reasons for poor warm-up.

Fan not working

The most commonplace reason, it happens, is that the fan does not work, it is not corny blown, and, accordingly, warm air enters the cabin poorly, or rather, does not enter at all. Of course, the stove radiator will warm up, but for heating the entire cabin, this is extremely insufficient.

You need to replace the fan or the electronics that controls it. Or look at the fuse, often it just blows it too.

Insufficient coolant level

This is now unlikely, because on many modern cars there are antifreeze level sensors - antifreeze. However, such cases take place (say, in cars of previous generations). Imagine - it’s gone (maybe due to a leak in radiators or pipes), enough heated liquid does not enter the stove, and it is almost cold, the fan blows, and the air is cold (it simply does not heat). You need to add coolant to the level (like this). Also, if radiators or pipes are leaking, then you need to fix the leak.

It is worth noting that when the coolant leaks, “air locks” can form, so even if you add antifreeze - antifreeze, you need to wait a while for the air to escape to the level.

Furnace radiator clogged

There may be several reasons:

The first one is . For example, in G13 you poured, say, G11 or TOSOL in general, then a precipitate may appear that will quickly clog all the thin radiator pipes.

Second, they poured water. Water causes not only rusting of metals in the system, but also forms scale on the walls.

Thirdly, they eliminated the leak of the stove radiator or the main radiator with all kinds of sealants. On the one hand we treat, on the other we cripple. The passages in the radiator can be clogged with excess of this sealant, the liquid cannot circulate normally in it, and, accordingly, heat it up, which means it will not heat up properly. True, your engine can show high temperatures, at the limit level (the main thing is not to overheat it). You need to either flush the system, clean the radiator, or simply change this radiator.

Faulty engine thermostat

Now for more complex breakdowns. If everything is fine with the stove itself, the fan works, but it does not heat well, then it may be the engine thermostat.

The thermostat serves to regulate the so-called "cooling circles". When we start the engine, the coolant goes in a "small circle", the engine and the interior stove are involved here. Thus, warming up is much faster. After the coolant has warmed up, the thermostat opens a “big circle” and the heated liquid has gone already and the main radiator, which is under the hood. This is done in order not to overheat the motor, if there is excessive overheating.

BUT from time to time or from the quality of the coolant, the thermostat can fail and not close the “big circle”, but always drive along it. Sometimes even an absurd situation happens when the small circle is (even) slightly blocked and slightly heated antifreeze goes into the stove (which should warm up the interior). It is blown to the maximum (maximum speed), but the air goes cold or barely warm. And since at -20, -30 degrees to wait until the “big circle” warms up for a very long time (and it may not warm up thoroughly at all), the interior will not warm up.

The solution is to replace the thermostat! Moreover, the sooner the better, yet the glass in your cabin will also not thaw, which is fraught in winter, because visibility is deteriorating.

Faulty engine pump

A pump is essentially a mechanical (sometimes electric) engine pump that pumps hot liquid through the system. That is, from the power unit block, through the pipes and further to the radiators, for cooling. And in our case, for heating the cabin.

It is an "impeller" that is inserted into metal cylinder through which the liquid passes. The impeller rotates, thereby pushing antifreeze (TOSOL) through the system. If there were no pump, then the cooling of the motor would be extremely inefficient, it would quickly overheat.

Very often the pump is driven by a belt drive from crankshaft power unit.

The main breakdowns are:

• Sometimes the belt breaks from the crankshaft, the pump does not rotate and does not drive the “cooler” through the system. Accordingly, the stove does not heat up. However, power unit will overheat.
• Wedge the pump itself. It does not rotate, or the inner part of the "impeller" does not rotate.
• eats up inner part. Due to the "shitty" quality of the metal, the inner impeller can be eaten by aggressive antifreezes or antifreezes. Therefore, purely physically, the pump pulley rotates, but the liquid pumps very poorly through the system. Again, the stove does not heat up.

For all reasons, the pump needs to be changed. I’ll say right away that the first “bells” may be - whistling in engine compartment, hot hose to the pump or stove, but cold after.

Broken head gasket

The thing is that the motor is not a monolithic structure, it has a block head and the block itself. They are connected through a special gasket. If this gasket is broken (and this happens, for example, with a bad broach), then the coolant will go into the cylinders or the muffler (there will be from the muffler). Thus, the coolant will not be enough in the system (possible manifestation air locks) and therefore the stove will heat badly! It is urgent to change the head gasket, otherwise you can kill the engine through overheating.

Probably, these are all the main reasons when the stove does not heat well! From myself I want to note that in most cases this is a thermostat malfunction (about 70%). So the first thing to check is to change it.

Now a small useful video, watch.

And that's all, read our AUTOBLOG.

With the advent of cold weather, many motorists remember one of critical devices- interior heater. Moreover, this happens, in most cases, precisely when the stove suddenly ceases to perform its functions properly, and it becomes unbearably chilly in the car. We understand why the car stove is naughty, and we improve the work of a regular heater.

How does a car oven work?

Before looking into the reasons bad work full-time car heater, it will be useful to delve into the principle of its work. In a nutshell, this simple device functions as follows.

In the vast majority of modern cars, the engine cooling system is responsible for heating the interior: hot coolant passing through the engine cylinder jacket moves through the pipes to the radiators - the main one (engine cooling system) and the heater radiator (which is located in the car). Through the latter, a small fan circulates the air entering the passenger compartment. The air streams warmed up by a hot radiator are distributed on air ducts and create comfortable temperature in the car.

Thus, the heating of the air inside the car is primarily related to the temperature of the engine and the liquid that cools it - the higher it is, the easier and faster the interior warms up. However, there are many other components in the system that increase or decrease efficiency. regular stove dampers, valves, filters, radiators, fans and air ducts themselves. We will study the influence of each of the components on the operation of the stove and try to make them function more efficiently.

Note that before you start troubleshooting the heater, it will be useful to remember the following. different models vehicles by virtue of their design features heat the cabin differently, especially in frosty conditions Russian winters. Normal, according to experts, is the situation when at -25 ° C overboard working on full power the stove heats the lower part of the car interior up to +16°С, and the upper part - up to +10°С. However, this is only minimal. allowable temperature which is not comfortable for most drivers.

Heater radiator pollution

The efficiency of the heater radiator depends on three main factors - its effective surface area and materials, bandwidth and the temperature of the coolant passing through it.

This small-sized radiator is hidden behind the center console of the car and is almost inaccessible to revision by ordinary motorists. It is extremely problematic to check the condition of the part visually, and replacing it with a new one sometimes results in many hours of disassembly and assembly of the entire front of the car (of course, for an immodest fee).

The stove radiator is a very delicate part and is afraid of any pollution - both external and internal. At long-term operation car, the radiator fins become clogged with dust and dirt that enters the system along with the outboard air. And the thin tubes through which the coolant circulates are overgrown with dirt from the inside. As a result, the efficiency of the system drops sharply - the airflow decreases and the temperature of the radiator decreases. This is the most likely reason for the cold inside the car in winter.

What to do

After several years of operation of the machine, it is best to replace the heater radiator with a new one, without waiting until it begins to perform its duties poorly. Contamination of this element of the system is inevitable and impossible to prevent. In addition, over the years there is a real danger of a violation of the tightness of the saloon radiator, which in some cases leads to a sudden breakthrough of the tubes and severe burns to the front riders. But more often, the radiator begins to gradually etch the coolant - it flows under the interior flooring, causing bad smell and strong fogging of glasses from the inside, and also contributes to the processes of corrosion of the body.

Thermostat failure

A faulty thermostat, which helps keep the coolant temperature in the system within set limits, is the second most likely cause of a cold cabin in winter.

This small part serves to automatically redistribute the flow of coolant in the system. In the engine warm-up mode, the thermostat closes and allows the antifreeze to circulate only in a small circle, a large circle (including the main cooling radiator) is connected only when the coolant temperature reaches a normal value. The fork of operation of a conventional mechanical thermostat is quite small - only 10–15 degrees from fully closed to fully open. When the valve hangs in the open position, the antifreeze constantly circulates in a large circle, which, under conditions sub-zero temperatures, does not allow it to warm up normally. The stove of the car, of course, also does not warm up well.

An indirect sign of this trouble is the incorrect position of the temperature gauge on dashboard- the arrow either does not rise to a normal value, or jumps strongly.

What to do

Remember: without a working thermostat, your car interior will never be truly warm in winter. To identify its malfunction, use a simple and effective technique. Open the hood and find all the hoses of the engine cooling system. Then find the thick pipes leading to the radiator and carefully touch them with your hand. A few minutes after starting the engine, they should remain cold. If they start to heat up quickly, the thermostat is not closing all the way and should be replaced.

Pump failure

The coolant is driven through the circuits of the cooling and heating system of the passenger compartment by a water pump - a pump. It, in turn, is driven by a gas distribution mechanism drive. The higher the engine speed, the more pressure the pump creates and the faster it runs through the radiators and pipes hot antifreeze(which means it gives off heat to the cabin). On some models of cars, the pump breaks in the most insidious way - the impeller of the device falls off or starts to scroll idle on the shaft. In severe cold weather, this does not lead to a sharp overheating of the engine, but the temperature in the cabin drops rapidly, putting the owner of the car into a stupor.

What to do

In the event of such a breakdown or insufficient efficiency of the pump, it should be replaced with a new one. If she refuses, there is a high probability serious damage engine, so it's not worth experimenting.

Airing the cooling system

Considerable troubles are brought in winter and unobvious, but very nasty malfunction- airing the engine cooling system. Such a breakdown occurs when outside air enters the circuits through which antifreeze circulates - if the pipes and their connections are leaky, leaks in the radiators or if the cover breaks expansion tank. Recall that the system is closed loop, in which, during operation, a certain operating pressure(Without it, the antifreeze will simply boil). When air enters the circuits from outside, the stove also ceases to heat up normally - approximately the same thing happens as in ordinary apartment heating radiators.

What to do

To expel air from the system, first of all, you need to find the source of its penetration - a leaky hose or other trouble spot. Then - eliminate leakage or air leakage and bring the antifreeze level to normal (usually airing is accompanied by a systematic drop in the coolant level in the tank). And, of course, release the air through a special bleeder (usually on one of the upper hoses under the hood). This breakdown accompanied by gurgling under the dashboard. If you hear these sounds, there is definitely a problem, and the operation of the stove can and even needs to be improved.

Air line pollution

Often, none of the previously mentioned malfunctions can be detected, but the stove still heats mediocre. It is possible that the matter is in the air lines themselves, the heater motor or the air filter.

On the way to the cabin, the outboard air travels an impressive distance in the air ducts and pipes. First of all, he gets into air filter, then it passes through the air conditioner evaporator (if any), is driven through the stove radiator by a motor and is broken into streams by curtains, depending on where exactly the driver wants to direct the air. Each of these components can be guilty of poor pressure.

What to do

First of all, pay attention to the heater motor and its modes of operation. The electronic unit that regulates the power of the air supply often stops switching normally and freezes in one of the lower positions. The engine itself also wears out over time and sooner or later completely stops working. This is preceded by rustling or creaking sounds.

Check the condition of the cabin filter. Being dirty, it creates a strong resistance to air flow and does not allow the stove to warm up the interior normally in extreme cold.

Check the operation of the flaps that regulate the direction and power air currents. Sometimes they no longer normally block the supply channels and reduce the efficiency of the system in certain positions.

Monitor the condition of the air conditioner evaporator - if there is no filter (on budget models) all the dirt settles in it, while it is extremely difficult to flush the system.

Do not forget about the cleanliness of the heater core itself. Over the years, it also acquires dirt despite all the filters and preventive measures.

Useful life hacks

And, finally, a few useful life hacks to improve the operation of the stove in the conditions of the Russian winter.

We close the radiator

On some car models sold on Russian market, electric shutters of the cooling radiator are installed as standard or plastic screens are applied, by installing which, you can partially block the flow of incoming air to the cooling radiator. It's simple and effective method speed up the heating of the cabin and improve the operation of the stove in extreme cold. In the absence of such devices, you can make them yourself. However, it is important to take all precautions in order to prevent self-ignition of the screens - they should not come into contact with hot elements of the engine compartment.

Reduce the air flow through the stove

In severe cold, some motorists increase the air flow through the heater radiator to the maximum, and are surprised that the stove still does not warm up the interior well. The secret is simple: passing through the stove on high speed, impressive volumes of cold air simply do not have time to warm up. By reducing the speed of the motor, you will increase the heating of the cabin.

We open the window

In some cases, the very design of the car, more precisely, an ill-conceived ventilation system, interferes with good interior heating. With non-working body ventilation valves and good sealing of doors in the cabin, high blood pressure and almost no air comes out. It becomes more and more difficult for the heater motor to pump oxygen into the car every minute. By lowering one of the windows slightly, you will increase the air circulation through the stove and, possibly, improve the climate in your car.

Experiment and you will surely find the best way increase the efficiency of the stove specifically for your car!

The heating system of a car for many models is arranged and works on a similar principle. Understanding the principle of turning on and adjusting the speed of the interior heater fan will be very helpful when looking for a malfunction on your own (for example, if you have one).

General air circulation pattern

The intake of air into the passenger compartment is carried out by a fan, which can be installed in the passenger compartment or behind the motor shield. Above the electric motor is located. If heating is required, the air flow passes through the heater core. The stove radiator is connected to the car's cooling system, so when the engine heats up, the circulating liquid from the engine cooling system heats the stove radiator cells. Therefore, passing through the honeycomb, the air flow also becomes warm.

Air flaps

The redirection of air flows for temperature control is carried out by a special damper. Damper control types:

• mechanical. The damper drive is connected directly to the switch in the passenger compartment by means of rods and cables. In this case, the driver, moving the regulator, manually doses the temperature of the incoming air;
• electronic. The damper is equipped with a servo drive. The electric motor changes the position of the damper, receiving commands from the control unit. This scheme is used on vehicles with climatic installations. It is enough for the driver to set on-board computer the desired temperature in the cabin, after which the electronic control unit, focusing on temperature sensors, will control the air damper servo.

Channels go from the stove fan into the cabin, through which air can be supplied to Windshield, at the feet or through the central deflectors. Depending on the scheme of operation, the modes can be either combined or single, when all the intake air is supplied to only one zone. Mode switching can be carried out mechanically or with the help of a servo drive and a control unit. mechanical method involves a direct connection of the air dampers to the switch on the dashboard. The electric damper drive allows you to control them by pressing a button, as well as to realize automatic control electronic unit interior air conditioning systems.

recycling

In recirculation mode, the main air damper, after which the stove fan begins to take air from the passenger compartment. This mode of operation allows you to block access unpleasant odors and polluted air from the street, if you, for example, follow a car on a dusty gravel road.

In winter, the recirculation mode allows you to warm up the car interior faster, since not frosty, but warm cabin air passes through the heater radiator. Accordingly, in the summer, recirculation simplifies the cooling process for the air conditioner.

Types of recirculation drive:

How does a stove fan work?

The fan of the car interior heating system is conventional engine alternating current. It can be either a simple axial fan or a diametrical version, which is most often installed on modern cars. The device of the inside of the stove fan is no different from the device of a conventional AC motor with excitation from permanent magnets.

Of greater interest to us is the operation of the electric motor on different speeds. This possibility is realized by including additional resistance in the circuit. Resistors increase resistance, which reduces the amount of current flowing in the circuit. Therefore, the fan starts to rotate more slowly. The value of the resistor determines how much current will drop in the circuit. Last speed fan is direct because no resistance is included in the circuit. This allows the heater fan to remain operational even if the resistor fails.

Wiring diagram

The figure shows the simplest circuit diagram oven fan connection. When the positive terminal of the switch, which is protected by a fuse, is closed to terminal H, current flows directly to the motor, causing it to rotate with maximum speed. When the positive contact is closed with the V pin, current flows through the resistance, which reduces the fan speed.

The heater motor of the VAZ 2108, 21099 models already has 3 fan speeds. When the positive output of the mode switch is closed to 1 contact, 2 resistances are connected in series in the circuit, so the rotation speed of the electric motor will be minimal. When power is applied to the second contact of the mode switch, the current will flow through one resistor, which will correspond to average speed rotation. Accordingly, pin 3 is designed to supply power bypassing the additional resistor and corresponds to the most fast speed rotation.

This is the principle of turning on the heater electric motor on most cars. For a better understanding of the scheme, we suggest watching the video.

Automated control system

In the diagram, we still see an additional resistor, only now all commands are transmitted to the electric fan not directly from the speed switch knob, but through the heating system control unit (No. 3). The block also controls solenoid valve recirculation of the passenger compartment and a micromotor reducer of the damper drive. This scheme uses only one temperature sensor in the cabin, but in more advanced versions there are also intake air temperature sensors, as well as sensors that measure the temperature of the air supplied to the passenger compartment at several points.