How does the starter solenoid relay work?


Starter solenoid relay is an electromagnet that performs two functions in the ignition system. The first is to bring the Bendix starter gear to the flywheel ring gear. The second is its return to its original position after starting the engine. A breakdown of the solenoid relay may result in the engine simply won't start. There are not many reasons for relay failure. In this material we will try to describe the signs and causes of failure, as well as diagnostic and repair methods.

Solenoid relay with core

Operating principle of the solenoid relay

Before moving directly to the malfunctions and methods for eliminating them, it will be useful for car owners to know the device of the starter retractor relay and how it works. It is immediately worth noting that the mechanism is a classic electromagnet , consisting of two windings (holding and retracting), a circuit for connecting it to the starter, as well as a core with a return spring.

Scheme of operation of the solenoid relay

When the ignition key is turned, voltage from the battery is supplied to the coils of the solenoid relay. This creates an electromagnetic field that moves the core located in its body. That, in turn, compresses the return spring. As a result of this, the opposite end of the “fork” moves towards the flywheel.

In this case, the gear connected to the bendix is ​​squeezed out until it engages with the flywheel ring. As a result of engagement, the contacts of the built-in starter circuit are closed. Next, the retracting winding is turned off, and the core remains in a fixed position with the help of a working holding winding.

After the ignition key turns off the engine, voltage to the solenoid relay stops supplying. The anchor returns to its original position. The fork and bendix, which are mechanically connected to it, disengage with the flywheel. Thus, a malfunction of the starter solenoid relay is a critical failure due to which it is impossible to start the engine.

Starter solenoid relay diagram

Solenoid relay circuit

In addition to the previous point, we present to your attention a diagram of the starter retractor relay . With its help, it will be easier for you to understand the principle of operation of the device.

The solenoid coil of the relay is always connected to the negative side through the starter. And the holding winding goes directly to the battery. When the relay core presses the working plate against the bolts, and “plus” is supplied to the starter from the battery, then a similar “plus” is supplied to the “minus” output of the retractor winding. Because of this, it turns off, and the current continues to flow only through the holding winding . It is weaker than the retractor, but has sufficient strength to constantly hold the core inside the housing, which ensures continuous operation of the motor. The use of two windings allows you to significantly save battery energy when starting the engine.

There are relay models with one winding - pull-in. However, this option is unpopular due to significant battery consumption.

Signs and causes of relay failure

External signs of a broken starter relay include the following:

  • When you turn the key in the ignition switch, no action is taken to start the engine, or starting is possible only after making several attempts.
  • After the engine starts, the starter continues to rotate at high speed. This can be heard by ear by the strong buzzing of the mechanism.

A malfunction in the relay is one of the reasons that the car does not start, and there may be several reasons for its breakdown:

  • failure (burnout) of the contact plates inside the relay (popularly called “nickels”), reduction in their contact area, “sticking”;
  • breakage (burning) of the retracting and/or holding winding;
  • deformation or weakening of the return spring;
  • short circuit in the pull-in or holding winding.

How to check the starter solenoid relay with a multimeter

If you find at least one of the listed signs, then the next step to fix the problem is to conduct a detailed diagnosis.

How to check the solenoid relay

There are several methods for checking the solenoid relay. Let's look at them in order:

  • The operation of the relay can be determined quite simply - at the moment of startup, a click is heard produced by the moving core. This fact indicates the serviceability of the device. If there is no click, it means that the starter retractor relay does not operate. If the retractor clicks but does not turn the starter, then the likely reason for this is that the relay contacts are burnt.
  • If the solenoid relay is activated, but a peculiar rattling noise is heard, then this indicates a malfunction in one or both relay windings . In this case, the starter solenoid relay can be checked using an ohmmeter by measuring the resistance of its windings. It is necessary to remove the core and return spring from the housing, and then check the resistance between the windings and ground in pairs. This value should be within 1...3 Ohm. After this, insert the core without a spring, close the power contacts and measure the resistance between them. This value should be 3...5 Ohm (the value depends on the specific relay). If the measured value is lower than the indicated numbers, then we can talk about a short circuit in the circuit and failure of the windings.

Do-it-yourself diagnostics of the engine starting device

For accurate diagnostics, you need a stand for testing generators and starters, which service stations are equipped with. But you can diagnose the starter yourself.

To carry out diagnostics correctly, you should know the basic rules and sequence of work:

  • First of all, the starting device is diagnosed,
  • Next, the traction relay is checked,
  • then the armature and brush assembly are checked,
  • At the final stage, the Bendix is ​​diagnosed.

For a general check of the starter, it must be dismantled and clamped in a vice. The unit must be securely fixed, but not tightly clamped, so as not to cause mechanical damage during testing. Then you need to take a piece of wire and close the contact bolts. A working mechanism will begin to move. In this case, there is a possibility that the solenoid relay is faulty.

You can check the starting unit using the battery by connecting it directly. To figure out how to connect the starter directly to the battery, you need to study the connection diagram. The body of a securely fastened starter must be connected to the negative terminal of the battery, and the positive terminal to the switching contact of the device and the upper terminal of the solenoid relay. If the device is working properly, the engine will turn the gear and the bendix will extend.

To check the retractor, you need to connect the relay and the positive terminal of the battery with one wire, and the body of the device with the negative terminal of the battery with the other. If the relay is working properly, the armature will advance the gear and a characteristic sound resembling a click will be heard.

The next thing to check is the device's armature. To do this, you need to apply 12V voltage directly to the starting unit, bypassing the traction relay. In this way, it is impossible to determine exactly what is faulty: the brushes or the armature windings. The cause of the malfunction can be determined visually by disassembling the unit. You can additionally check with a multimeter.

Bendix is ​​a device responsible for the silent operation of the starting unit. To check, the dismantled bendix must be clamped in a vice. When doing this, use a soft cloth to avoid damaging the device. The Bendix clutch should only turn in one direction. If it rotates in both directions, then the cause of the malfunction is its breakdown. In this case, the part must be replaced.

Photo gallery

1. Checking the starter bendix 2. Checking the armature and brushes 3. Checking the brushes for ground 4. Diagnostics on a special stand

Repair of starter retractor relay

Worn relay contact plates

On many modern cars, the solenoid relay is made in a non-separable form. This is done for two reasons. First, this increases the reliability of the mechanism and its durability due to mechanical protection from external factors. The second is that automakers want to make more profit from the sale of their components. If your car has just such a relay, then the best solution in this case is to replace it. Write down the brand of the relay, its technical parameters, or better yet, take it with you and go to the nearest store or car market for a similar new one.

However, some car owners repair it themselves. But at the same time you need to know how to disassemble the starter solenoid relay . If the relay is collapsible, then it can be repaired. In the case of non-dismountable parts, repairs are also possible, but to a small extent. In particular, when burning “nickels”, improving and cleaning the contact. If one of the windings burns out or short-circuits, then such relays, as a rule, cannot be repaired.

During dismantling, mark the terminals so that you do not confuse them during installation. It is also recommended to clean and degrease the relay and starter contacts.

For further work you will need a flat blade screwdriver, as well as a soldering iron, tin and rosin. Disassembling the relay begins with the fact that it is necessary to remove the core from it. After this, two are unscrewed that hold the top cover where the coil contacts are located. However, before removing it, it is necessary to unsolder the mentioned contacts. In this case, it is not necessary to solder both contacts . Usually, to get to the “nickels”, it is enough to unsolder only one contact and lift the cover on one side.

Disassembly and repair of the solenoid relay

Repair of the retractor relay VAZ 2104

Next, you need to unscrew the bolts holding the “nickels” from the top side and remove them. If necessary, they need to be reviewed. That is, clean them with sandpaper in order to get rid of carbon deposits. A similar procedure must be performed with their seats. Using a plumbing tool (it is best to use a flat blade screwdriver), clean the seat, removing dirt and carbon deposits. Reassembling the relay housing occurs in the reverse order.

Disassembly and assembly of a collapsible relay occurs in the same way. To do this, you need to unscrew the stud bolts and disassemble its body. This will give you access to the internal elements of the device. The audit work is carried out similarly to the above algorithm.

REPLACEMENT

We figured out where the starter relay is located on the VAZ 2114, now all that remains is to find out how it can be changed. There are two options for replacing this part:

  • With the removal and installation of the starting unit itself;
  • Without removing the starter.

In any case, you should have the necessary tools:

  • Combination key 13;
  • A screwdriver (it would be better to have several of them - Phillips and slotted ones);
  • Key for 10.

A set of keys is always necessary to have in stock. Let's look at how to replace the solenoid relay on a VAZ 2114 with removing and installing the starter (by the way, this is much easier to replace):

  1. Remove the battery terminals;
  2. Unscrew the two bolts securing the air filter housing (10mm wrench);
  3. Disconnect the connector of the air flow sensor (MAF);
  4. Unscrew the air pipe clamp and dismantle the housing;
  5. We pull off the wire chip of the solenoid relay (held on a plastic clip);
  6. Using a 13mm wrench, unscrew the nut securing the positive terminal;
  7. We unscrew the fastenings of the starter itself (it is secured with three 13 nuts);
  8. We take out the mechanism;
  9. With the starting device removed, use a 13mm wrench to unscrew the wire on the VR cover going to the stator winding;
  10. Using a screwdriver, remove the three screws securing the VR and dismantle this device.

Now you need to install the new part and put everything back together in reverse order. That's it, the replacement of the retractor on the VAZ 2114 is completed. Of course, you can try to get to the relay mounting screws right in place without removing the starter, but it’s up to you to decide how easier it is to remove this device.

Types of solenoid relays and their manufacturers

Let's briefly touch on the solenoid relays used on VAZ cars. They are divided into four types:

  • for non-geared starters of VAZ 2101-2107 (“Classic” models);
  • for non-geared starters of VAZ 2108-21099 models;
  • for VAZ gear starters of all models;
  • for AZD starter gearboxes (used in VAZ 2108-21099, 2113-2115 models).

In addition, as mentioned above, they are divided into collapsible and non-collapsible. Older models are collapsible. New and old are interchangeable .

For VAZ cars, solenoid relays are produced by the following companies:

  • Plant named after A.O. Tarasov (ZiT), Samara, Russian Federation. Relays and starters are produced under the KATEK and KZATE trademarks.
  • BATE. Borisov Automotive and Tractor Electrical Equipment Plant (Borisov, Belarus).
  • Kedr Company (Chelyabinsk, Russian Federation);
  • Dynamo AD, Bulgaria;
  • “Iskra” A Belarusian-Slovenian enterprise whose production facilities are located in the city of Grodno (Belarus).

When choosing a particular manufacturer, it is necessary to take into account that the highest quality and most common brands are “KATEK” and “KZATE”. Also remember that if an AZD starter is installed on your car, then “native” relays manufactured at the same enterprise are suitable for them. That is, they are not compatible .

Results

The starter retractor relay is a simple device. However, its failure is critical , as it will not allow the engine to start. Even an inexperienced car owner with basic plumbing skills can check and repair the relay. The main thing is to have the appropriate tools at hand. If the relay is not removable, we still advise you to replace it, since, according to statistics, after repairs are completed, its service life will be short. Therefore, if the solenoid relay does not work in your car, buy a similar device and replace it.

Selecting a part for a VAZ-2110

Often the entire starter assembly is replaced, but we recommend not doing this. The pull-out relay is much cheaper than the entire kit.

The choice of a new relay should be approached with the utmost seriousness, since the quality of the part will determine how long it will serve the owner.

Most VAZ-2110 are equipped with a solenoid relay manufactured by Bosch, with catalog number 2339303293 . The cost of the part is about 2000 rubles.

Analogs

In addition to the proposed version of the original part, there are quite a lot of analogues that can be installed on a car. So, many car enthusiasts do just that. Let's look at what the automotive spare parts market offers the owner of a 2110:

    Cargo 131143 – the cost is 1200 rubles. High quality for little money.

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