It is possible to open a car with a dead battery in any of the closure options - with keyless entry, with the alarm on, or simply with the central locking activated. If the alarm system does not have an autonomous power supply, then in all of the above cases there is a single algorithm for how to open the door and get into the car interior when the battery is dead. But keep in mind that there are not only universal methods for opening a car if the battery is dead, but also their own characteristics for specific brands and models of cars. If you don’t know them, then read the article.
If the alarm system has an autonomous power source, then when the car doors are opened, the system will “scream”. However, using the methods given in the article, you can reduce the noise time to a minimum after starting the engine. Or turn off the alarm completely. Having listened to all the advice, opening the car if the battery is dead will not be difficult.
Key
The most logical way to open the car if the battery is dead is to use the key. Often the car does not respond to turning the key. It requires some effort to open it. Turn left and press lightly.
Find out the charging time of your battery
Opening car doors with a key
In the cold, the larva may freeze and not work at all. Silicone lock lubricant or WD 40 should help.
If they are not there, it’s a long way to run to the store; it may be easier to find a medical syringe, vodka or alcohol at home. We draw alcohol into a syringe and inject it into the larva according to the VDshka principle. It is better to clean up spills immediately with a rag. If your hands suffer from frost, place your palm on the lock, the thawing process will go faster. After 5-10 minutes the key will turn the lock.
You can simultaneously revive all the doors into which the key must be inserted, this will increase your chances of getting inside. Even if it is difficult to get into the passenger compartment from the trunk of the car, its lock also needs to be opened. Once in the trunk, you will have access to the wiring through the backlight bulb.
How to open a car alarm if the battery is dead
In order to open the car alarm if the battery is dead, you need to supply power to it . This will not only unlock the lock, but also deactivate it. How this can be done will be discussed below.
| Situation in which the battery is discharged | Energy source |
| In the garage |
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| In the country |
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| On the road |
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| In the courtyard |
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| In the parking lot/parking lot |
|
To open the car, if the battery is completely discharged (for example, when the battery is old or dead due to severe frosts, or because you forgot to turn off the lights), simple power is not enough, you will need to wait some time for the battery to recharge. In this case, the machine alarm will definitely go off, since it will reboot. But this inconvenience can be easily eliminated by turning off the “signaling” using the key fob.
Using a tonometer or a wooden wedge
Opening doors with a wooden wedge
A blood pressure monitor cuff will help you open the door or hood of your car when the battery is dead. Instead, you can use a wooden wedge, they need to work more carefully, there is a chance of damaging the body.
With a tonometer or wedge, it is more convenient to perform an autopsy with two people, but one can also do it.
We make our way into the salon, we will need a wire, rod or something similar about a meter long:
- place the deflated cuff between the door and the body of the car with a discharged battery;
- inflate it with air until a gap is formed, minimally sufficient, less than 1 cm, to manipulate the wire through it, without harm to the body;
- use wire to hook the latch or door handle, depending on the design of the door and your abilities.
The video clearly demonstrates the described method.
In a similar way, the edge of the hood is bent to get to the battery terminals. The method makes sense if there is no battery cover. It is safe if you know the location of the positive terminal under the hood. You cannot perform such an operation at random; it is dangerous to confuse the terminals. We provide access to the battery:
Car keys
- place a cuff without air between the hood and the body;
- inflate it until there is a gap sufficient to insert the wire to the battery.
To restore power supply, another battery will be required. Having a free working car, we take it and use it. If not available, a drill or screwdriver may be available. Their battery should be enough to trigger the alarm button. The main thing is to connect the plus to the plus; the minus can be connected to the body.
We use the key
It would seem that the problem can be solved using a regular key fob. But, if the battery is completely dead, then its energy will not be enough to open the door. In this case, it is logical to try to unlock the car mechanically. And here several problems may arise at once.
If it happens in winter, then, most likely, the castle larva is covered with ice inside. In this situation, it is enough to arm yourself with alcohol and a lighter (the beloved WD40 is not an assistant in this case). After this, we heat the key and insert it into the well. After performing this operation several times, you can defrost the lock and get into the car. Or you can pour a little alcohol into the larva. The hot liquid will quickly melt the ice and release the lock.
However, this method will be completely useless if the car is equipped with a modern alarm system that simply blocks the locks. In this case, the key can be inserted into the cylinder, but it cannot be turned. In such situations, you have to resort to other tricks.
Features of individual car models
The best way to restore power sometimes depends on the make of the car.
Emergency opening of car doors
The battery terminals under the hood are easily accessible in the Mazda CX7 and Passat. Minimal bending of the edge of the hood will be required, but it may be possible to do without it. Also, many Passats have a power outlet in the trunk. If the trunk can be opened with a key, you can power the Passat through the socket and open the car with the alarm button. Once you reach the cable from the hood, you can pull it and open access. On the Passat, the cable runs behind the front left fender liner, which can be removed.
For emergency opening when the battery is low, Mercedes provides a positive terminal hidden in a plastic box at the bottom in the area of the front wheels. We connect the minus to ground. Charged from a working battery, the Mercedes will open with a button.
There are owners with experience in opening Mercedes by removing the rear license plate illumination. Its wires are used to charge the car, then open it with a button. Behind the light there is a pneumatic hose through which air is supplied when the trunk is opened. If you manage to get a hose and blow into it hard enough, it should unlock all the doors.
Battery in a car
BMW also outputs the “+” terminal in the bottom. Depending on the model, its location differs; if you have seen your car from below, most likely you know the exact location. Lighting a cigarette and starting it through such a connection is not particularly convenient, but reviving the BMW alarm system is a solution.
Nissan does not have an emergency terminal in the bottom. You can get into the car's electrical network from the street only by removing the fog lamp cover or repeater. The most acceptable way with Nissan is to revive the larva. It will be effective to provide clearance under the hood to the discharged battery or into the passenger compartment. The methods described above are applicable to Nissan.
Features of different car brands
The table shows options for getting into cars of different brands when the battery is dead.
| Brand | How to open doors |
| LADA | Using a mechanical key or connecting power to the turn signal, light bulb above the number |
| Hyundai | Open the hood, connect to the battery, turn signal, light bulb above the license plate |
| Ford | Open the hood, connect to the battery, turn signal, light bulb above the license plate |
| Toyota | Connect to generator or battery (through the hood) |
| Skoda | Connect to the turn signal or light bulb above the number |
| Volkswagen | Get into the cabin through the trunk or power the turn signal and light bulb above the license plate from an external source |
| KIA | Connect to the turn signal or light bulb above the number |
| BMW | Connect to generator |
| Mercedes | Connect to the turn signal or light bulb above the number |
German cars have a built-in emergency terminal, which is easy to connect to. BMW and Mercedes have a complex design of electronics and engine, so owners of such cars are recommended to contact a specialized organization.
Opening the trunk
Opening a car trunk
The battery is dead - how to open the trunk if there is only a button on its lid, there is no lock with a cylinder or it does not work? Such a door opens with the participation of the electrical network, so it is necessary to restore the power supply.
If you have access under the hood, you just need to get power from another battery. To activate the trunk button, it is enough to connect the positive terminal of the working battery to any plus in the car with a dead one; the minus can be short-circuited to the body. The above describes how to get inside if the battery is dead.
Having gained access to the car, it is important to establish the reason why the battery died and how discharged it is. The reason may lie in the battery itself, the generator, the wiring, or something else. It must be eliminated before normal use of the car. Otherwise, repairs may cost many times more.
How to connect to the battery to recharge if it’s dead and the locks don’t work
To connect to the starter of a car with a dead battery to recharge it without opening the hood, we attach the black terminal from the donor minus to ground, and the red crocodile from the positive terminal must be attached to the upper terminal of the retractor starter (a thick white or red wire comes from it)
Having used one of the methods and opened the doors, the dead battery must be recharged in any case, otherwise you will again soon have difficulties either opening or closing the door and setting the car alarm. You can also recharge the battery a little, and then just open the locks.
To recharge a car battery, it is not necessary to remove it; you can charge it on the spot, without even opening the hood (if you have any difficulties with it). Moreover, for this it is not at all necessary to open the hood (or trunk, if the battery is located in the rear of the car). And to do this, you need to connect the crocodile wires for lighting to the power terminals . These are the terminals on the generator or starter .
Lighting a cigarette or recharging the battery through the backlight and turn signal will not work since large currents are needed to recharge the battery, and accordingly, the standard wiring may not be able to withstand it!
Starting the generator
You can open a car with a dead battery simply by starting the generator directly. If it starts, it will be able to recharge the battery, and accordingly, the central locking will open. Powerful energy sources (high current) are not needed to start the generator. To do this, you can use any 12-volt DC source (another car battery, a motorcycle battery, or even a screwdriver).
Please note that the cross-section of the wires used to start the generator must be at least 5 mm²! It is best to use special wires for lighting.
You can crawl into the generator either from below from the pit, or simply by jacking up the car. An additional difficulty may be created by its location or the need to remove the engine protection.
The wire from the positive terminal of the second battery must be connected to the thickest positive wire on the generator, and the negative wire to the “ground” (body) of the car. After power is supplied, the central locking can be opened using the key fob. And if you are using a second car battery, you can start the engine so that the generator starts working and charges your dead battery under the hood.
Connecting to the starter
Opening a car using the central lock and starter, using Skoda as an example: video
You can also open the alarm if the battery is dead by connecting to the starter. To avoid unscrewing or removing anything, crawl underneath and connect the wires from the second battery to the positive terminal of the starter (it has a large thick red wire) and the ground of the car. Once connected, the central locking will open simply from a signal from the key fob. This method will allow you to start the engine and, due to the operation of the generator, recharge the battery. Just take thicker wires!
It is necessary to connect with wires for “lighting”, since they can withstand high current. And the external power source must produce a current of 400 Amps and above. The starter startup time should not exceed 5 seconds! Otherwise, either the wiring or the starter itself may burn out.
Professionals
Of course, if this happens to you, and you just can’t open it. You can call specially trained people. Now there are a huge number of services that will come to your aid. They also have equipment, and in such cases they, as they say, “ate the dog.”
However, it is not cheap, from 500 to 2500 rubles. It depends on how complex the work is, and the class of the car. Therefore, this is not our option, but it’s worth talking about. If you don’t want to suffer, just call and call
Is it possible to open a car with a dead battery?
To get to the battery, you need to open the hood. Usually this can be done from inside the car, but if you can’t get into the car due to lack of keys or for some other reason, you will have to try to get into the engine compartment. On some car models, it is enough to unscrew the left handicap and remove the radiator grille. On older cars, there may be more problems with opening the hood, but they can be solved. We'll tell you how later.
Having reached the battery, it is fashionable to recharge it or use the neighbor’s to open the doors.
In a word, there is a solution to the problem, and more than one, but there are no universal methods; each time you need to use what is suitable specifically for your model. Of course, it is advisable not to harm the car. But often sacrifices have to be made, especially if the situation is urgent.
How to power a generator
The above method may not always be used. The design of some cars does not allow the hood to be lifted slightly. You'll have to connect the generator. This procedure is much more complicated. To work you will need:
- Jack.
- Additional battery.
- Copper wires - 2 meters, diameter 2 mm.
- Spanners.
The front of the car is raised with a jack to a height that allows a person to carry out operations under the car. To organize safety, stands are placed under the car. The protection of the power unit is removed from below. It does not allow you to freely work with the generator.
One end of the copper wire is connected to the generator positive. The second one is fixed on the positive side of the additional battery. The negative is connected to the machine's ground in an accessible place. As soon as the power supply to the generator is restored, the door will open after pressing the key fob. All that remains is to charge the battery well.
You can organize meals in another way. However, it is much more complex. An in-depth knowledge of the vehicle's on-board electrical network is required. Similar methods are used by technicians working at service stations. They disassemble machine parts that block access to electrical wiring. Wires are connected in certain places to organize the supply of electricity.
How to lock a car
To close the central lock before disconnecting the battery, for example, if you plan to take it away for storage or recharging, you must first force the lock to operate.
The engine turns off, the ignition is turned off, but the key cannot be removed. After this, you can press the button on the door, the lock will work. The key is removed, the door opens using the inner handle, and is locked through the outer cylinder. The hood must first be opened.
You can remove the battery and slam the hood, the car will be locked with all the locks. It opens after that with the same mechanical key. It is advisable to check its operation first and lubricate it if necessary.
Extreme measures
Such methods are resorted to only in desperate situations. When you have tried everything possible, if all actions did not give a positive result. The easiest way is to take a heavy hammer and break the glass. Any heavy object will also work. Some cars are equipped with a small window. To cause minimal damage, it is better to break it.
Sometimes they resort to a more barbaric method. They just drill out the door lock. The door will, of course, open, but the consequences will be too expensive. All the locks will have to be changed.
There is an original option when a special “blank” key is used. Its design makes it possible to crash into the door cylinder. By pressing on it, you can turn the key and the door will immediately open. Unfortunately, after such a mechanical impact, it is impossible to do without repairs. To never encounter such problems, always monitor the condition of your battery. Do not allow it to become completely discharged. Only then will you never have to open the car using the methods described above.
Mechanical door folding
This method is used only if it is impossible to slip a wire or rope. You'll have to open the door. The pad described above will be useful for this. If it is missing, a wooden wedge of a certain size is driven in.
The operation must be performed very carefully. To ensure that the paint coating remains undamaged, a rag is placed between the door frame and the body with a screwdriver. By bending the door slightly, it becomes possible to throw the wire around the handle and pull it hard. The door will open. If this is not possible, you can try to lift the clamp.
Power Delivery Technology
To power a dead battery, you need to have:
- A special pillow.
- Copper wires. You will need 2 meters, with a diameter of 2 mm.
- Extra, well-charged battery.
The pillow is inserted into a thin gap between the hood of the car and its body. Then, using a bulb, air is pumped into the pillow. Wires are inserted into the enlarged slot. They are fixed on any positive terminal. The hood lid bends away from the side where the battery is located.
The free end is connected to an additional battery. Its minus is connected to the ground of the machine. A wheel nut or any unpainted surface will work for this. Special “crocodiles” secure the wires perfectly.
What can cause a car battery to discharge?
There are plenty of reasons for an emergency reduction in voltage at the battery terminals:
- loss of capacity due to natural aging, manufacturing defects or poor care;
- failures due to internal breaks and short circuits;
- energy balance disturbances, the battery is discharged more than charged at low temperatures and short trips;
- long-term storage of the car, in the on-board network there are always unswitched consumers with low power, but over a long period of time they “pump out” the battery;
- forgetfulness of the driver, who leaves on more powerful consumers, lights, multimedia, heating and other equipment, with which cars are now oversaturated;
- high internal self-discharge current of a tired battery;
- external leaks due to conductive dirt.
The result is always the same - the voltage gradually drops, after which a certain threshold will be crossed, beyond which not only the starter, but also the central locking with remote control or the security system will not work.
On the subject: What does the peephole on the battery mean: black, white, red, green
The battery could be recharged or replaced, but the hood opens from the interior, which is not accessible.
Open the hood
The main problem is that there is no power in the car circuit. However, if you replace the battery or light it, then you can open the car. BUT it's not that simple. Opening the hood of a closed car (under guard) is quite a task!
Nowadays, many hoods are held on by a special loop, which engages with the lock hook (we pull the handle from the interior - this hook comes off - the hood opens).
Many people write that you can also do this from the outside, just take a screwdriver and crawl through the decorative radiator grille. I don’t know, it seems to me personally that this doesn’t work, because the grille can be almost cast (there’s simply nowhere to get to), or it’s located too far away. In general, this is also not our method.
