There are many reasons why a car's central locking system may fail or stop working stably. Sometimes the weather is to blame for malfunctions, namely too high humidity, excessively low temperatures and similar climate features. But sometimes problems arise due to incorrect installation of the lock itself, incorrect adjustment, as well as normal wear and tear due to long-term use.
1. Localization of central locking faults
Experts conditionally divide all problems that may arise with the central locking into several groups:
1) Complete or partial failure;
2) The lock works, but with malfunctions due to electrical or mechanical defects, or due to damage.
If the central locking of your car is acting up, then try to determine which category the defect belongs to. Repairs should begin not with disassembling any parts, but with diagnosing the equipment, which will significantly reduce the time for repairs, and sometimes the financial costs of this event.
The operation of the central locking should not depend on the operation of the engine, or whether the ignition is turned off or on. The most important thing is that the on-board network works, that is, the power terminals must be connected to the battery.
The entire system is formed by switches connecting wires and drives, on which the type of central locking will depend. The central lock can be electric, and its drive will also be electric, that is, presented in the form of solenoids or mechanisms with a motor. If the central lock is pneumatic, that is, vacuum, then its drive will be vacuum, and the drive will be formed from a control board, a compressor and pipes. Often, drives are called activators or actuators. The control drive is mounted in the door on the driver's side, and sometimes on the passenger's side. If this drive is triggered, an electrical signal is sent through special wires that will open or close the remaining doors.
If your car has an alarm, then repairs should begin with testing it. If, when using a portable alarm remote control, the central locking does not respond, then you need to check the operation of the lock from the button and key, which are responsible for opening and closing the door on the driver’s side. If, during manual control, the lock is triggered, then the problem lies in malfunctions of the control and electrical circuits of the alarm itself. First of all, you need to check the battery that is in the remote control. She may be discharged.
2. If the lock does not work at all or partially
If, after manually checking the operation of the central lock, it still does not work, then you need to determine what the problem is, that is, specify the nature of the defect. If the vacuum central locking fails completely, you will not hear the compressor running. In the case of an electric central lock, you will hear faint clicks that the relay will make, and the buttons for self-opening will not work on all doors. If this is the case, then you need to check and, if necessary, install a new fuse for the central locking circuits. It may be necessary to change several fuses, depending on the electrical circuit of the machine.
There is a possibility that this will be enough to normalize the work, and the repair will end there. If at the moment when the central locking is activated, one of the fuses burns out, then this indicates that there is a short circuit somewhere in the circuit that this fuse protects. In this case, you need to look for the reason why the short circuit occurs. If all the fuses are in order, but the central lock cannot be opened manually, then the reasons may be the following:
1) The supply wires could break, or due to oxidation the contacts are poorly connected to the terminals, so there is no voltage at the input of the driver’s door activator, that is, the control signal cannot be transmitted by the drive to the other doors. There is simply nothing to transmit the signal with;
2) The limit switch of the driver's door activator is broken, or the wires that extend from the control terminals are broken, or the contact at the terminals is too poor, that is, there is no control signal.
Repair work must begin by checking the presence or absence of power and control signals of the wire at the moment of activation of the central locking, that is, you need to check whether there is voltage at the corresponding terminals. Then you will need to check the wires for quality and integrity. At the very end you need to check the limit switch, which will need to be repaired or even replaced if necessary. The switch in the case of electric central locks is always located inside the drive.
The central locking may not work if there is a breakdown in the electronic alarm circuit of the car, and in the case of a vacuum central locking, the compressor board may also be broken. They need to be checked and repaired at the stage of completing diagnostic work. If the central locking still responds, then this is a case of a partial defect, that is, you can hear the compressor of the vacuum central locking working, or you can hear the relay clicks of the electric lock.
Door buttons for manual opening may work partially or not on every door. They can also quickly switch from the “closed” to the “open” position and vice versa. Such defects can occur due to broken fixation of the fasteners of the rod, which goes from the drive to the locking mechanism. This can happen in the doors both on the driver’s side in case of poor operation of all activators, and in other doors if the opening and closing process in them is disrupted.
3. Repairing partial failures of the vacuum central locking
Often, such breakdowns of the central locking are accompanied by an atypically long operation of the compressor (15 - 20 s, or even more):
1) Until the pump stops working, the car doors open and close with a central lock;
2) All the doors either opened or closed, or some lock did not work, and the compressor hums until it is turned off by the protection.
In the first case, a breakdown may occur due to too much condensation or due to breakdowns associated with the contacts of the activator switch. That is, voltage goes from the drive along both control wires to the pump board, there is a “+” that goes to both closing and opening, which is why the compressor alternately pumps out and pumps air. In this case, you will need to check the switch, and if necessary, replace or repair it. There may be several reasons for the breakdown in the second case:
1) The vacuum line tubes are leaking;
2) The signal to open or close the lock does not reach the compressor control board from the limit switch of the activator of one or more doors. The pump continues to work;
3) Signals about opening or closing locks are not received by the compressor, despite the fact that they reach it.
In the first case You must first check the line to the door where the drive does not work. You can find the area where there is damage by the characteristic hissing of air. Pipes that are damaged must be replaced. If the hoses are intact, the problem lies in the leakage of one of the drives. Often, the membrane on one of them is damaged, or the wire itself breaks. If you could not find the required membranes or actuator, you will have to buy the door lock itself.
If the problem falls under second case, then repair work must begin with diagnosing the electrical circuits going from the door actuators to the control board, checking for the presence of voltage on the corresponding wire. To do this, you can simply compare the state of all circuits from all drives. Most likely, the incorrect signal comes from a single wire, and the voltage on the bundle of wires that contains this “broken” one will not be the same as on the conductors from other bundles. Then you will need to find the break in the circuit and fix it. Often, damage occurs in the area of door corrugations. In case of integrity of the wires, the cause of the malfunction must be sought in the limit switch, which will have to be either repaired or replaced.
In the third case you will need to disassemble the compressor unit and clean the terminal contacts of the pneumatic alarm sensor for opening and closing. Most likely, the terminals have oxidized. If after such repairs the lock still does not work, then you should check the control board circuit. It will need to be repaired.
4. Repair of electric central locking
Central locks with domestically produced solenoids, several years after the start of use, begin to act up due to temperature fluctuations, and they are especially badly affected by cold weather along with high humidity, which is typical for autumn and spring. First, the solenoids jam, and then they may completely refuse to open and close the locks. Often, this situation is typical for cars whose central locking was installed at the factory. It would be better to replace them with drives with a motor, but you can still try to carry out repair work. If the activator of one or more doors does not operate at all or only partially operates, this indicates that:
1) There has been a break or broken contact in the power circuit running from the activator switch from the driver’s door to the power relay (directly or through the control board) and then to the inoperative drive;
2) The relay has failed;
3) The control board is broken;
4) The wires are broken or the contact on the motor terminals or solenoids inside the activator is broken;
5) The activator gears with the motor or its moving parts are worn out;
6) The motor winding or solenoid coil has burned out.
You need to start repairs by checking the voltage supply to the drive that does not work. Voltage should go to one wire at the moment the closing function is activated. At the moment of opening, the voltage on this wire should disappear, and on the other, on the contrary, it should appear. Then, based on the diagnostic results, you will need to check either the activator itself and repair/change it, or the circuit that goes from it, in “pieces”, then this is the area before the relay along with the control board, then the relay itself and the wires after it . Damaged areas will need to be repaired. Most often, in the central locking system of a car, the wires in the corrugation between the body and the door break.
The standard central locking does not open
You open the driver's door of the car with the key, but the other doors do not open, although according to the logic of the central locking they should open.
The simplest and most common reason may simply be a blown fuse. When it burns out, the electrical circuit of the lock stops working, although you can easily open or close the doors mechanically (with a key).
I don’t know how it is in others, but in Chinese cars assembled by Derways, the contact chip from the driver’s lock could easily fly off. Typically this chip has five contacts. To check this possibility and put the chip in place, you will have to unpanel the door. This is done quite simply, both on Solano and Geely MK or Cross. A screw near the inside handle to open the door and a screw inside the handle to close it. The door panel itself is held on by plastic clips.
In addition to the chip, the microswitch in the electric drive of the driver's door lock may fail. Its function is to close the circuit when the key is turned and open or close the remaining doors. If you have a standard central locking remote control and the doors open with it but not with the key, then the reason is in the driver's door lock.
If the doors do not work when using the remote control (buttons on the key), then either the fuse is at fault, or the BCM unit does not receive or transmit a signal. In the smiley, this block is located under the steering column; you need to unscrew two screws and fold back the plastic cover. On Solano and Lifan x60 it is fixed under the heater control panel. On Geely Mk above the fuse box in the passenger compartment (on the right). On the Emgrande it is also under the steering column to the right of the driver’s feet.
Also, one should not exclude the cause of contact rubbing in the door harnesses. This is still rare, since the cars are all relatively new.
Electric locks do not open when controlled from an alarm system
If there is no standard remote control on the key, but there is a third-party alarm and it does not open the doors, then the first thing you need to do is also check the fuses. And not only the car itself, but also the alarm system. To do this you need to know. Where is the central car alarm unit located? Typically, blue and green wires, or blue and green with a white stripe, are used to control the central locking. Fuses are mounted using a hinged method directly on the wires.
Of course, the signaling itself could also fail. Listen when you press the remote control buttons - are there characteristic clicks of electromagnetic relays in the alarm unit? If not, then check why. Maybe the battery is dead or the remotes have lost synchronization with the unit. Try reprogramming the remotes according to the instructions for the alarm. If there are clicks, then either the fuses or the wiring are to blame.
By the way, in winter, the load current consumed by the central lock increases due to weather conditions. As a result, fuses may blow out more frequently.
There can be many reasons for the breakdown or unsatisfactory operation of the central locking system. Some of them are caused by climatic conditions (high humidity, cold winters, etc.), and some are caused by improper installation and adjustment or wear.
Localization of central locking faults
All malfunctions of the central locking system (CL) can be divided into the following categories: complete or partial failure; The lock does not work or malfunctions due to mechanical or electrical defects or damage. When identifying malfunctions of the central locking system, you should rely on this classification and begin repairs not with any specific actions, but with diagnosing the equipment. This will save a lot of time, and possibly finances.
- there is no voltage at the input of the driver's door activator due to a break in the supply wires or poor contact at their terminals as a result of oxidation - the drive cannot transmit a control signal for the remaining doors (nothing);
- The limit switch of the driver's door activator is faulty or there is poor contact at its control terminals or a break in the wires coming from the control terminals - there is no control signal.
The repair should begin by checking the presence of power and control signals (appearance or disappearance of voltage on the corresponding contacts) of the drive when the central locking is activated. Then they check the quality of the contacts and the integrity of the wires of the corresponding circuits. The last thing to check is the limit switch, which is repaired or replaced if necessary (in electric central lockers it is always installed inside the drive).
The cause of the failure may also be a malfunction of the vehicle's electronic alarm circuit, and in the case of a vacuum central locking system, it may also be a failure of the compressor control board. They are checked and repaired at the very end of the diagnosis. If the central locking shows at least some “signs of life”, then we are talking about its partial failure - you can hear the sounds of the compressor operating in a vacuum central locking system and the clicking of a relay in an electric one.
Door buttons for manual opening may partially or not work on all doors, or they may move from the “closed” to “open” position and immediately back (or vice versa). One of the reasons for this behavior of the central lock may be a violation of the fixation of the fasteners of the rod going from the drive to the lock mechanism (in the driver’s door, if all the activators are not working well, or in the one in which the unlocking/locking process is disrupted).
Repairing partial failures of the vacuum central locking system
Most often, malfunctions occur that are accompanied by prolonged operation of the compressor (for 15–20 s or longer until its protection is triggered):
- The central locking opens and closes the car doors (and vice versa) until the pump turns off.
- All the doors opened/closed or the lock did not work on some (possibly uneven operation of the locks), and the compressor continues to hum until the protection turns it off.
The reason for the 1st case may be: a malfunction or “floating” due to condensation or other reasons; the contact of the driver’s door actuator switch - voltage is supplied from the drive via both control wires to the pump board (“plus” for both opening and closing - in As a result, the compressor either pumps air or pumps it out). It is necessary to inspect the switch and, if necessary, repair or replace it.
In the 2nd case it could be:
- Leakage of vacuum line tubes.
- From the limit switch of the actuator of one (or several) of the doors, the signal that the lock has closed/opened does not reach the compressor operation control board, and the pump continues to circulate air.
- Signals about locking/unlocking the locks come to the compressor board, but it “ignores” them.
In the first case, first check the line to the door with a non-operating drive. The damaged area can be identified by the hissing of air. Broken tubes are replaced. If all the hoses are intact, then one of the drives is leaking - usually the membrane in them is torn or cracked. If there is no suitable membrane or used actuator, you will have to purchase an assembled door lock.
In the second case, the repair begins with checking the electrical circuits from the door actuators to the control board for the presence of voltage on the corresponding wire. You can simply compare the state of all circuits from all drives. Most likely, the incorrect signal is coming from only one drive, and the voltage measurements on the wires of the bundle coming from it will be different from the readings on the wires from all the others. Then you should find the open circuit and repair it. Most often, damage occurs in the door corrugations. If the wires are intact, then the reason lies in a faulty limit switch, which is being repaired or replaced.
In the latter case, it is necessary to disassemble the compressor unit and clean the contacts of the opening/closing alarm pneumatic sensor terminals - most likely, they have oxidized. If this does not help, then you need to check the control board circuit - it needs repairs.
Repair of electric central locking
After several years of operation, domestic central locking systems with solenoids begin to be afraid of downward temperature changes, especially in conditions of high humidity and in the autumn-spring period. The solenoids first begin to jam, and after some time they may completely refuse to open/close the lock. They are usually found on cars with a factory-installed central locking system. It is better to replace them with drives with a motor, but you can try disassembling them, cleaning them and lubricating them with fresh grease.
Failure to operate or partial activation of the activator of one or more doors can be caused by:
- a break or poor contact in the supply circuit from the driver's door activator switch to the power relay (directly or through the control board) and after it to the inoperative drive;
- relay failure;
- control board malfunction - if any;
- poor contact or broken wires at the terminals of the motor or solenoid inside the activator;
- wear of the activator gears (with motor) or its moving elements (for all drives);
- burnt motor winding or solenoid coil.
Repairs begin with checking the voltage supply to the drive that does not operate as it should. Voltage should be supplied to 1 wire when the “close” function is activated.
When opening, the voltage should disappear on this wire, and appear on the other. Then, depending on the test results obtained, either the activator itself is checked and the fault in it is eliminated, or the entire circuit before it separately (before the relay, including the control board, if any, then the relay itself and the wiring after the relay) restoring the functionality of the damaged areas . The most common breakdown in the central locking system is a wire break in the corrugation between the door and the car body.
Central locking is an indispensable attribute of a modern car. Many car enthusiasts practically do not use a mechanical lock to open doors.
For this reason, mechanical lock cylinders, due to corrosion and diffusion processes, literally get stuck to the lock structure, and if the central locking system malfunctions, the battery is low, the key fob or car alarm malfunctions, access to the car interior may be limited.
Signs of a central locking malfunction
The main symptoms of a central locking malfunction correspond exactly to their manifestation:
- The driver's door does not open with the key fob or key;
- The driver's door does not close with the key fob, key or button;
- opening and closing one of the doors does not work;
- central locking closes and immediately opens the doors;
- The locking is triggered spontaneously and the doors open.
In one expression, all of the listed malfunctions can be called “incorrect operation of the central locking system.”
The central locking system belongs to the category of complex electronic systems of a car; troubleshooting its faults is quite complicated, so soberly and carefully assess your ability to independently eliminate such a fault.
Video - the central locking in LADA KALINA stopped working, searching for the reason:
How the system works
The central locking system includes the following main blocks and components:
- central electronic unit;
- driver's door electronic unit (can be combined with the central unit);
- electronic units for driver, passenger and rear doors (may be missing);
- push-button switches for driver, passenger and rear doors;
- limit switches for closing windows and doors;
- control units and window lift drives.
In most car models, the power window and central locking control units are connected into a single system. When closing the doors, the central locking system must poll the limit switches of all windows so as not to accidentally park the car and guard it with the windows open. Therefore, the failure to close the doors is often associated with a malfunction of the window regulator controls.
For a 2005 VW Passat, the electrical circuit for the central locking looks like this:
- Drive, buttons and limit switches of the passenger door (hereinafter referred to as Dv);
- Passenger engine control unit;
- Window lifter control unit and rear left drive;
- Rear left drive motor, switches;
- Driver's switch;
- Driver's driver's side switches;
- Driver's control unit, internal;
- Control unit for rear right door and window lifter;
- Multifunctional control unit.
- Blocker.
- Central locking drive rear right motor
- Window lifter switches and buttons.
- Fuses serving the central locking system.
This diagram does not show and label all the elements, but it is clear that the circuit is very complex, perhaps the most complex among the main electronic modules of a car.
At the same time, the central locking control circuit has the longest electrical wiring, which is distributed throughout the vehicle interior and has flexible corrugated hoses at the points of transition to the door space. Among other difficulties, car doors have maximum mobility relative to the interior; their interior space is susceptible to corrosion.
Despite the above difficulties, car models after the 2000 release have fairly reliable electronic central locking systems; their main malfunctions are often determined by mechanical breakdowns, faulty contacts, and wear on the door suspension.
The main causes of central locking malfunction
The main causes of malfunction of the central electronic locking system are:
- malfunction of electrical wiring, especially in places of corrugated hoses and connectors for entering the motor (up to a quarter of all failures);
- improper adjustment and operation of limit switches, power windows, window regulators;
- incorrect adjustment or wear of the closing mechanism of the motor, wear of the suspension of the motor;
- damage to rods and plastic tips;
- malfunction of the door lock drive;
- malfunction of power window drives;
- failure of the engine control buttons;
- malfunction of the power window control buttons;
- blown fuses;
- malfunction of the electronic control units included in the central locking system.
In modern cars, they try to structurally combine electronic door controls into a single whole with drives, limit switches and control buttons.
With the combined option, the probability of failure of the central locking system is reduced significantly. This reduces repair and maintenance time. To carry out repairs, for example, the driver's door, a unit replacement (entirely) of just one central drive with a control unit and limit switches is required. This, of course, negatively affects the cost of repairs.
Independent circuit repair of the central locking system without the appropriate experience and knowledge is almost impossible. However, some typical faults can be eliminated if they are not related to damage to the electrical wiring.
If the central locking from the key fob does not work: troubleshooting sequence
Any repair or troubleshooting in a car must begin with checking the fuses that serve a specific system. There are three of them in the diagram below. Usually it can be more. You need to find their location using the car's instruction manual or searching on the Internet.
Video - if the central locking does not work from the alarm, then first check the fuses:
If all fuses are in good working order, proceed to determining the location of the malfunction based on its characteristic symptoms.
1. Central locking does not close the doors
There are several options for central locking:
- does not respond to the key fob signal at all, in this case it is necessary to check, or better yet, immediately change the key fob battery;
- does not close the door even with the lock key;
- closes and immediately opens the doors.
The last option is associated with loose closure of windows or doors. It is necessary to try to press each door in succession, supporting it with your whole body, and at the moment of pressing, try to close the central locking.
Perhaps a foreign object has gotten into the closing area of a door; it needs to be checked. You should also check the pressure of the glass so that it fits tightly into the upper grooves.
If the central lock does not respond to the key fob and key, the wires may have broken in the area of the corrugation entering the door. If you have experience repairing electrical wiring, you can find the faulty wire and connect it.
2. The central locking system does not open the doors, but closes them
One option is to shift the door hanger. The lock is locked with a door latch. This type of malfunction often occurs in the trunk doors. You have to press them manually to wedge the movement of the lock drive. When you try to open the door, you should hear a click from the drive. In some cars it is almost inaudible; you have to put your ear to the door.
3. Central locking only closes the driver's door
Here, most likely, the malfunction is a breakdown in communication from the driver's door control unit to the central unit or other doors. You should remove the corrugated hose from the wiring transition from the driver's door to the car interior - there will be a break there.
In some car models, there is a connecting connector at the junction of the wiring into the car interior; you can check its contacts. It is also necessary to examine the electrical wiring under the door trim and all connectors.
4. Opening one of the doors does not work
Possible malfunctions: damage to the electrical wiring in the corrugation or on the way to it in the cabin, malfunction of the lock drive.
Video - the central locking of the driver's door on a Skoda Fabia does not work:
The lock drive is easy to replace and is inexpensive. During replacement, the main thing is not to damage the levers, rods and plastic tips.
If you replace the central locking drive yourself, to be sure, it is better to find a mechanical diagram on the Internet, reference books, or the instruction manual so that you do not forget to install any part.
Periodically open the door with the key, even if you always use the central locking key fob, so that the door lock mechanism does not get stuck.
Do not try to warm the lock with hot water if it is frozen in winter. It's better to try an electric hair dryer. Commercial liquids for freezing at low temperatures do not always help.
A large number of modern cars are necessarily equipped. This is not the most reliable security element for a vehicle, but in combination with an alarm it allows you to achieve a truly high level of protection. If the first central locks (CL) caused a lot of controversy and were considered not reliable enough, as the automotive industry and security systems developed, the situation changed for the better. But locks can still fail from time to time. And if their proper operation is disrupted, the car owner should definitely know why this could happen and what to do in a particular situation. There are several variants of malfunctions, each of which requires a certain algorithm of action on the part of the car owner.
Recommendations for repairing the central locking of a car.The central car lock consists of:
- central electronic unit;
- electronic units for front and rear doors (not always present);
- driver's door electronic unit;
- push-button switches for all doors;
- limit switches for closing windows and doors;
- control units and window lift drives.
In most cases, the blocks responsible for are directly connected to the central locking and combined into a single system. When the doors are closed, the central locking checks the condition of all doors and windows so that they are not left open when closing and activating the alarm. The central locking system cannot be considered a separate element of the car. This is the name of all system components responsible for locking the locks in the vehicle. The task is to simultaneously open and close doors, raise and lower windows, and sometimes also be responsible for opening the fuel tank lid.
The operating principle is based on the fact that when you turn the key in the driver's side door lock, a microswitch is activated, which is responsible for the locking process. From it a signal goes to the door control unit, and then to the central unit. From there, control signals are distributed to each of the existing control blocks. This allows you to simultaneously close all doors, windows, etc. When you turn the key again, the reverse process occurs, that is, unlocking. Depending on the type of device, the central locking system may be triggered. The second option involves using a special button on the car keys.
The occurrence of any malfunction in the operation of the central car lock instantly manifests itself in the form of a violation of its functionality. In this case, the signs or symptoms of a breakdown correspond to what exactly happened to the system. Therefore, problems can be identified by the following nuances:
- it is not possible to open the car using the key fob;
- opening does not work when using the key;
- the key fob does not lock the car;
- or a button when closing the door;
- one of the doors does not open or does not open;
- The central locking is triggered, closes everything, but immediately opens without a corresponding command from the driver;
- locking and unlocking work spontaneously.
We can say that malfunctions manifest themselves in the form of incorrect operation of the system. The central locking system is a complex device that consists of a large number of components and control units. This is a whole network of electrical wires, which sometimes covers the entire car. Given the complexity of the system, consideration should be given to who will carry out the repairs. It is often recommended to entrust this to specialists. At the same time, every motorist has the right and opportunity to know what malfunctions occur with the central locking, what is their cause and how they can be dealt with. Whether to repair it yourself or trust the experts is a purely individual question.
Types of faults
There are a lot of situations and cases when central locks on cars do not work. But it is important to understand exactly what happened and how the malfunction manifests itself. Mostly malfunctions manifest themselves in the form of a refusal to respond to certain commands. Sometimes the system opens completely. Mostly motorists are faced with the following situations:
- the castle behaves unstable;
- partial failure is observed;
- The central locking system does not respond to commands from the key fob;
- the system does not respond to commands from the key.
Each of the presented situations requires separate consideration.
Unstable work
There are cases when the central locks on cars have not stopped working, but their behavior and functioning can be described as unstable. That is, they can work normally when commands are given, but at some point give out unexpected surprises. Basically, instability at work manifests itself as follows:
- When the driver presses the key fob button, incorrect operation of the control unit or module is observed. The block either reacts to commands or completely ignores them and does not execute them. One time everything functions perfectly, no problems arise, but the next time there are failures. When sending commands to the central locking from the remote control, they may or may not be executed;
- When trying to open the door locks, at first the system opens them normally, but after a while it opens them spontaneously. Although the driver did not give such a command. Locks can behave similarly when receiving a closing command. The doors lock and then unblock themselves;
- When the driver presses the button to open the doors, the control device closes them. And when you try to close the door, the opposite situation occurs, that is, the doors open;
- After pressing the open or close button, only part of the car doors carries out the command. One or more doors do not respond to signals, or perform actions opposite to the command.
It is obvious here that the central locking system really behaves unstable. Situations like this don't happen so rarely. But specialists will be able to find the cause and also help in restoring normal performance. Some car owners cope with the situation on their own.
Partial failure
Here we are talking about situations when the central locks do not close, although it is possible to open the vehicle doors using a key or key fob. Here we are also talking about the fact that the central locking does not work, but this occurs in the form of a partial failure. If the driver tries to close the doors with the button, he will not succeed. Then you can close them mechanically, that is, by pressing the corresponding buttons from inside the cabin. After this, the key fob will normally unlock the doors, but will no longer be able to close them back. Such a malfunction indicates that the central locking system has partially failed. Here the problem should mainly be found in the electronics of the system.
Central locking does not respond to key fob
Many car owners note that the central locks installed on their vehicles often stop responding to commands sent through the key fob, that is, the control panel. In a situation like this, there could be several potential reasons why the central locking may not work. Namely:
- The communicator itself has failed. It's okay, but the situation needs to be corrected. Mostly the reason lies in the discharge of the power supply;
- There are problems with the operation of the control device. That is, the fault is in the remote control itself, and not in the system.
For many drivers, the option of a faulty remote control is much more attractive, since replacing it will quickly solve the problem. If the fault is in the system itself, repairs can be significantly more expensive and also take more time to find the source of the problems.
Central locking does not respond to the key
Usually there is nothing to worry about in situations where the control panel does not work. There is always an alternative way to lock or open doors using a key. But sometimes it also happens that after inserting the key into the lock, nothing happens. That is, the key itself has failed. There is a high probability that there is a mechanical problem with the lock. If your car has another door with a lock, you can try to open the car with it. Regardless of the nature of the malfunction and its manifestation, there is a problem with the central car locking system. And it needs to be solved. Even when the remote control has stopped working, but all manipulations can be carried out with the key, it is recommended to restore the key fob in order to always have the possibility of alternative access. After all, at some point the key itself may fail.
Causes of problems and solutions to problems
Previously, only signs of malfunctions were considered. Now it is important to understand why they arise, who is to blame for this and what needs to be done in a given situation. Central locking failure is usually associated with:
- relay failure;
- wiring problems;
- battery;
- fuses;
- keychain;
- control device;
- actuator.
Considering the fact that there are many causes of malfunctions, each of them requires separate consideration. After all, the approach to repairing the central locking system directly depends on who was the culprit of the malfunctions. Motorists should be warned in advance. If you are not confident in your own strengths and capabilities, and do not have experience in repairing complex systems such as central locking, you should not try to repair the central locking system yourself. This is sometimes a complex procedure that requires appropriate qualifications and a clear understanding of the structure of the entire system.
Relay
A fairly common cause of malfunctions in the operation of the central locking system, when the car central locking does not open from the key fob, is the relay. Therefore, the motorist needs to check its current condition. You can do this yourself, since the procedure is not the most difficult. First you need to find the place where the relay is located. It may vary depending on the make and model of the vehicle. In some cars, the relay is installed together with other relays and fuses in a special block. But sometimes the element is located on the section of the electrical circuit that follows from the control unit. You can look at the instruction manual and find out exactly where the relay you are looking for is. Having found it, it is necessary to dismantle the device for further inspection. Checking is carried out with a multimeter. You can also disassemble the relay and check the condition of the board, which is located inside the case. If there are traces of burnt contacts, it will not be possible to restore the relay. It just needs to be changed. Experienced drivers and specialists recommend trying to close the electrical circuit directly after dismantling. If nothing has changed, all that remains is to simply throw out the old relay and put a new element in its place. It is inexpensive, but in a few minutes you can fully restore the operation of the central locking system. When choosing a new relay, it is recommended to take the old failed component with you. This will allow you to accurately select a similar device.
Wiring
Most often, electrical wiring suffers in the area that runs between the body and the door. It provides for the use of rubber corrugation, and wiring runs inside it. If it is damaged or interrupted by accident, or during active use, the central locking system will cease to function. When the circuit is open, due to the bending of the line, the contacts are closed, which allows the lock to function normally. Once it is closed, the contacts will open and the device will stop working. To solve the problem, it is recommended to follow a few simple rules.
- Open the car door. While it is open, press the close button. To do this, a rod in the form of a screwdriver or other available material is inserted into the lock latch from the end side. If everything is fine with the wiring, after such manipulation the lock should work and try to close the door
- Next you need to press the limit switch. He is in the doorway. This is necessary for the control module to record the fact that the device is closed.
- The car's security system is turned on if it has an alarm system. In this case, the door locks must be closed. If the alarm determines that the locks are closed, the driver will receive a response in the form of a sound signal.
- On the control panel, press the button to enable or disable the protection. If the door opens after pressing, pull the door handle, open the latch and slam it back. In a situation where the doors did not open, you should start looking for damage on the electrical line, that is, in the wiring.
The check is carried out by partial dismantling and ringing. Here you can use a multimeter. If the wiring is highly branched and you don’t know exactly where it leads and how to check it, it is better to entrust this work to specialists. Having discovered traces of a break, it will be necessary to restore the contacts, replace part of the wiring as necessary, and also provide reliable protection against repeated damage. To do this, use electrical tape. Additionally, you can place the wires in a special protective corrugation. Now act according to the situation.
Battery
A discharged battery can provoke a fairly extensive list of malfunctions associated with the electrically dependent equipment of the vehicle. Also, the battery can negatively affect the functioning of the central car lock. Most often, problems arise when the battery is severely discharged. Much less often, central locking failure is associated with battery replacement. But this mainly affects the alarm system. If you notice that the battery is low and the central locking is not working properly, the only solution to the problem is to charge the battery. If the battery completely fails and does not respond to the charger, you will have to replace the battery completely.
In order not to waste a complex diagnostic and dismantling work, first try checking the condition of the fuse responsible for the central locking. This may be the problem. At the same time, solving such a problem is extremely simple. Motorists are naturally interested in where the central locking fuses are located on their cars. Here you will have to look not only at the fuse box, but also at the instruction manual. The block is not difficult to find, since it is often located in the engine compartment. Just according to the instructions for your car you will be able to find a specific fuse, since there are quite a lot of them in the car. But everyone has their own specially designated place. There shouldn't be any problems with the search. And the fuse itself fails for two reasons.
- Short circuit. Although the fuse has blown, you must first find the source of the short circuit. To do this, the electrical circuit is checked. Only after elimination should the burnt element be replaced. Otherwise, each new fuse will burn out in the same way as the previous one.
- Overload in the circuit. An overload in an electrical circuit is usually due to the fact that one of the actuators, or rather their electric motors, begins to consume more electricity than they need. Overload is also possible due to improper operation of the rods and frozen lubricants. As a result, the motors have to put more effort into opening or closing the locks. Here you will need to disconnect each actuator one by one from the chip with wires and find the problematic element.
Fuses are cheap consumables that do not require large financial costs. But before you change them, you need to understand exactly why they burn out.
Keychain
If after pressing the remote control buttons there is no reaction from the central locking system, just try using the key. If the key works, then the problem is obviously in the key fob. It needs to be replaced or repaired. It is possible that the battery in the remote control is dead, or there is a problem with the electronic board. This usually happens after contact with water or when the key fob is left in a humid environment for a long time. Try drying the device first. If it doesn't help, you'll have to change the device. Sometimes contacts become damaged. If you have the appropriate tool, the contacts can be soldered.
Control device
If your central locking does not close the doors, or closes but does not open the doors, then there may be problems with the control module, which is installed in the driver's door, or in the electronic unit of the vehicle itself. Since the central locking is not functioning, you need to look for the source of the problem and try to fix the problem. To check, you will need a tester or multi-tasking multimeter. The condition and presence of voltage of the control circuit cables are assessed. Then check the power circuit. You should make sure whether there is voltage in it or not. To apply current, you need to turn the key in the driver's door lock, or press the corresponding buttons on the control panel. But keep in mind that to check the status of the control device, an electrical interlock circuit is required. If it is not there, then it will be difficult to find the required verification lines.
Actuators can fail for several main reasons:
- contacts have become acidic;
- mechanical damage to these contacts has occurred;
- the electric motor has failed;
- the gears of the gearbox are worn out;
- the gears were deformed and skewed;
- There were problems with the rods responsible for opening and closing the door locks.
To solve the problem, you will have to remove the covering materials from the door, get to the actuators, remove them and check them. First, mechanical cleaning of contaminants is performed. It is possible that the reason lies in moisture that has accumulated in the form of condensation. Central locks on cars are indeed very useful, but they are also quite complex security devices. Their performance depends on a number of elements. The failure of even one component can lead to the loss of functionality of the entire unit. Some breakdowns can be easily fixed on your own, but to solve other problems it is better to seek help from specialists.
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