How to Open a Car if the Battery is Dead
It is possible to open a car with a dead battery in any of the short-circuit options – with keyless entry, with the alarm on, or simply when the central locking is activated. If the alarm without self-contained power, in all these cases there is a single algorithm for how to open the door and get into the cabin auto with a dead battery. But note that there are not only universal methods, how to open the car if the battery is dead, but also its own characteristics for specific brands and models of cars. Do not know them – then read the article.
In the case of the alarm system has an autonomous power supply, the system will “scream” when opening the doors of the car. However, using the methods given in the article, you can reduce the noise time to a minimum after starting the engine. Or at all emergency disable the alarm system. Having listened to all the tips, it will not be difficult to open the car if the battery is dead.
Ways to open the car if the battery is dead
In different cars, if the battery is dead, you can open the door in different ways. Their choice depends on the peculiarities of the design and operation of the car’s electrical circuits. How to do this on the most popular cars information is collected in the table.
- Through the radiator grille, by connecting to the battery
- Through the license plate lights
- The central locking system opens with a regular key
- Power supply
- Short out the starter or alternator
- Through a rotary knob
- Wires cross section of 5 mm² or more
- Power supply
- Connect to the battery by opening the hood
- Through a light switch or license plate lamp
- Power supply
- Recharge the battery by opening the hood
- Supply power to license plate lighting
- Power supply
- Screwdriver Screwdriver for unbending grid
- Connect to starter, alternator
- Light the battery
- Supply power to license plate lighting
- Connect the battery to the auxiliary light on the roof (if available)
- Use the diagnostic CAN bus to deactivate the alarm
- Power supply
- Locksmith tools
- Jack, latch
- Connect power supply to the license plate lights
- Use another battery to power the alternator
- Power supply
- Wrench set
- Through the license plate lights
- Fog lights (if they were on)
- By starting the alternator or starter
- By opening the trunk with the key (if it is not locked by the central locking system), on many Volkswagen Passat in the trunk there is a socket. You can use it to power the battery
- Connecting wires
- External power supply
- Side turn signal light
- License plate light
- To close/open circuit between battery and central locking system
- Jack, latch
- Screwdriver keys
- Power supply
- Start with the alternator or starter.
- You might try connecting through the light
- Some cars have an emergency plus terminal on the bottom (its location depends on the car model)
- Jack, latch
- Cigarette lighter wire
- External power supply
- Tools – keys, screwdriver
- It’s better to try through the backlight and that’s it. The other methods can hurt the car.
- Shorting the alternator and starter will help, but it’s hard to do as you can damage the electronics!
- Some cars have an emergency plus terminal near the front wheels in a plastic box
- External power supply
How to open a car with keyless entry when the battery is low
Opening the car with a mechanical key
If the key fob does not unlock the car, the first thing to remember is that the main key and the spare key (with a red marking) are always equipped with a regular mechanical key which can be used to open the driver’s or front passenger’s door. The door locking mechanism itself has nothing to do with the car’s electrical system, so the doors can be opened in any case.
The only thing that can prevent you from doing this is a sour lock. If you constantly open the door with a key fob, the mechanism will stick and then to turn the key will have to lubricate the keyhole Vedeshka or silicone grease.
In some cars the lock is closed cap and to open it you need to fork it from the bottom with the same keyring or key tag keipasa.
When saturate the battery is not in the car, and the key fob (battery), then sometimes you can try to open not a door, and the trunk (the energy to open one lock is much less than all). Or, using two wires, try to feed the key with a bunch of two finger batteries or a battery from a cell phone.
Charging the key fob with a mobile battery
If the mechanical key can be turned, but the lock doesn’t unlock, you can unlock the car without the key and the key fob using the same methods as for the central locking opening. About which we will talk below. Here are just in some cases to unlock the keyless entry into the car to close the circuit between the central lock and the battery, and in other cases on the contrary open, it all depends on the type of lock. If the car is installed on a regular bolt, then the circuit must be broken. On models with magnetic lock, you can unlock the keyless entry in the car, on the contrary, by closing the circuit from the central lock to the battery.
A prime example is the Kia Sportage car. It can be opened by opening or closing the electrical circuit between the battery and the central locking system (central locking system). To access this circuit, you need to suspend the car and remove the right front wheel.
When the key does not open the doors (scrolls, but unlock does not happen), but only with the key fob, then to open the car if the battery died, – just apply power from the donor battery on the contacts of the license plate lights (do not mix up where the connector plus and where the minus).
It is also necessary to supply power in case it is necessary to open the hood (to charge the battery), where there is an electronic lock instead of a mechanical one. Only you can do it after opening the doors. Give the plus wire from another battery to the permanent plus of your car in the salon fuse box, and the minus one must be thrown on mass.
This way will allow you to feed a backup battery and open the hood or trunk lock with key fob or to remove the car with alarm/immobilizer lock.
How to open a car with an alarm, if the battery is dead
In order to open a car alarm if the battery is dead, you need to power it. This will not only unlock the lock, but also deactivate it. How this can be done will be discussed below.
- Another battery
- Power supply from PC / laptop
- Screwdriver battery (or other power tool)
- Battery type 18650 (most often used in LED flashlights)
- Light a battery from another car
- Light a cigarette from another vehicle
- Use a starter
- Light a car with another battery
In order to open the car if the battery is completely discharged (for example, when the battery is old or dead because of severe frost or because you forgot to turn off the light) just powering the car is not enough, you need to wait for some time for the battery to recharge. In this case the car alarm will be triggered for sure, because there will be its reset. But this inconvenience can already be easily eliminated by disabling the “alarm” with the key fob on the key.
How to unlock the central lock on a dead battery
Lubricating the door lock with WD-40
Since the actuator activator unlock/lock the central locking on the car doors work on the voltage supplied by the battery, you can open the door when the battery is dead after applying voltage from another power source. If the battery is dead and the central locking system does not work – supply voltage to the lock from an external source and then open it with a key fob. It does not have to be a car battery. The main thing is that the voltage is enough to activate the lock motor.
Or use your key and open the driver’s door lock manually. An exception may make those situations where the central locking works only with alarm or you have so long ago opened the lock with the key, that it got stuck or frozen in the cold because of moisture (when the situation happened in winter).
What to do if I can’t open the door with a key? In the case if you got dirt in the carkit or it is hardened (rusted), sometimes it is impossible to open it with just a key. Spray a defroster or some cleaner or liquid key to wash the lock cylinder. To make it easier to open the door, apply some pressure to the lock area when unlocking the door with the mechanical key.
How to open a car with a dead battery through the license plate light
It is possible to open doors and the trunk if the battery is dead through the car’s rear license plate light. The popularity of this method is that it works almost always, regardless of the purpose of simply opening the door locked by the central locking system or remove the alarm!
To open the car through the license plate light, you need to get to its contacts. The light can be inserted on the latch or screwed with one bolt. It won’t be hard to find out which is the plus and which is the minus – either use the color or check with a multimeter (if the battery is just flat). The black or brown wire is the minus contact, and the red, yellow or white wire is the plus contact. Throw in the wires from the other battery and apply voltage to the onboard network.
Connecting the second battery to the onboard network
Opening the car through the license plate lights – using a screwdriver battery
The current strength in this case is not important, since a small pulse is enough to unlock the central lock. Therefore, as an external source can be used another battery, a battery from a laptop, a few batteries type 18650 (usually used in LED flashlights and similar equipment) connected in series.
In most cases, when opening the car through the license plate light, you can not worry about the fact that it will lead to the failure of the individual elements of the car’s electrical system. In extreme cases, only fuses in the system can burn out, which are designed to protect the individual elements of the system.
The method is not suitable for cars where the exterior lights do not come directly from the relay system, but through the microprocessor. In this case it is better not to use the opening through the rotary knob!
How to open the car if the battery is dead through the rotary knob
You can also open the car if the battery died through the turn signal. This method is similar to the one described above. To implement it, you need to remove the side turn signal (preferably the left one, to reduce the distance to the central lock control unit). To remove it you will need a screwdriver (less often a special shaped wrench). If you can not pull it out, and there are fog lights, which are easier to remove, you can unlock the doors of the car through the PTF.
Connect one side of the wire to the socket for “plus” and “minus” also connect the other side to the battery for 12 volts. The main thing is to give a brief electrical pulse to the control unit of the central locking system. So if you don’t have a backup car battery, use any available 12 volt DC source.
Just don’t try to cigarette your battery from the neighbor car this way – you’ll burn the wiring!
How to connect to the battery to recharge it if it’s dead and the locks don’t work
To connect to the starter car with saturated battery for its recharge without opening the hood, the black terminal from the minus donor attached to the mass, and the red crocodile with a plus terminal must be attached to the top terminal retractable starter (it goes from a thick wire or red color)
Using one of the methods and opening the door, drained battery in any case should be recharged, otherwise you again soon have trouble with either opening or closing the door and setting the car to the alarm. You can also recharge the battery for a while and then only open the locks.
It is not necessary to remove the car battery to recharge it, you can charge it on the spot, and even without opening the hood (if there are difficulties with it). And to do this it is not 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 crocodile wires for cigarette lighter to the power terminals. Such are the terminals on the generator or starter.
Cigarette lighter or recharge the battery through the backlight and signal starter will not work as for charging the battery needs large currents, and, accordingly, regular wiring can not stand!
Start the generator
It is possible to open the car with a dead battery just by starting the alternator directly. If it starts, it will be able to recharge the battery, and respectively, will open the central locking. You don’t need a powerful power source (high current) to start the alternator. You can use any 12 volt DC power source (another car battery, a motorcycle battery or even from a screwdriver).
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 cigarette lighter wires.
You can get to the alternator from the bottom of the pit, or just by jacking up the car. Additional difficulty may be caused by its location or the need to remove the engine protection.
The wire from the plus terminal of the second battery should be connected to the thickest plus wire on the generator, and the minus to the “mass” (body) of the car. After powering the central locking can be opened with a key fob. And if you use the second car battery, you can and start the engine to start the generator and charge your dead battery under the hood.
Connecting to the starter
Opening the car with central locking and starter, on the example of Skoda: video
Open the alarm, if the battery is dead, you can also connect to the starter. In order not to unscrew or remove anything, get underneath and connect the wires from the second battery to the starter plus terminal (it has a big thick red wire) and the car’s mass. Once connected, the central locking will open simply from the signal from the key fob. This way will start the engine, and due to the generator, respectively, and recharge the battery. Just use thicker wires!
You need to connect with the cigarette lighter wire, as they can withstand a large current. And the external power source should give out 400 amps or more. Start time of the starter must not exceed 5 seconds! Otherwise either the wiring or the starter itself can burn out.
How to close the car when the battery is dead
Closing the car is much easier than opening it. Close the door if the battery is dead or the battery is dead in the key fob, you can either manually or with the help of service buttons. For most cars, the algorithm for closing the front right and rear doors will be as follows:
- Open the corresponding door.
- Make sure that the child safety lock (if any) is disabled on the rear doors.
- On the end of the door in the depth of the lock, you will need to move the latch to the closed state.
- Insert the key (or flat screwdriver) in the hole and, without turning it, to move the latch toward the inside panel of the door or put the flag down (it all depends on the model of car).
- Remove the key.
- Close the door and then make sure it is locked.
Location of door closing latch (on some cars it is not in the lock)
Locking the rear doors of the vehicle with the key fob latch
Note that on some cars the service latch is on the outside, usually under the door handle, closer to its edge.
Most Korean and Chinese cars have an internal door lock button. The easiest way to close the doors without a battery is to have a “doggie” on top of the inside door panel. Press it and slam all the doors one by one. If there is no such a key on the driver’s, then you will need to close it with the key.
Many European and domestic cars also have a similar key at the top of the door. So close the car with a low battery or its absence will not be a problem.
Well, and if you have a premium car with keyless entry, then you will need to close as well as open – using an additional power source.
When you just need to close the car and put on the alarm, with a working battery, but not having the key fob – just hold the button to close the door (the image of the door with the key). When it lights up and there will be a beep, you can close.
How do I open the car if the battery is dead?
When the battery is completely discharged, the car does not respond to signals from the key fob. Neither start the engine, nor open the doors or the hood will not work. From the article you will learn what to do if the locks and the alarm does not work. We will tell you how to open the car when the battery died.
Using the key
The battery is always discharged. It gives power to the on-board computer, car stereo, alarm and other important systems. And if the battery is dead, the electronics will not respond to the remote control commands. You won’t be able to open the doors, the hood or the trunk.
Then you will have to use the key. Find the lock latch, insert the key and turn it to the left – the door is open. In some cars, the locks are hidden under the decorative covers near the handles. You will need a screwdriver to remove them. But that is not the only problem.
If you haven’t used the locks for a long time, they will rust. And in the winter, they freeze. And to open them, you have to be crafty.
If your lock pick is rusty, liberally pour WD-40 or other liquid cleaner on it.
And if it’s frozen, rubbing alcohol will help. Put it in a syringe and pour it through the needle into the lock cylinder. Vodka or other alcohol will do instead.
Process all locks, including the trunk. So your chances of success will grow by 3-5 times. And most importantly, do not forget to remove the excess liquid with a rag. If it helped, be sure to stop by the service. You need to service the locks, and change the battery at the same time. And if not, then use other ways to open the car.
When the locks don’t work, you won’t be able to get into the cabin. Especially if the car has keyless entry. Therefore, you will have to act differently. The main goal is to get into the cabin, open the hood and put a new battery. To do this, you need to apply power to the alarm system.
Some manufacturers have provided for such an option and hid the backup terminals outside the body.
Mercedes-Benz installed the plus terminal in a plastic box at the bottom near the front wheels.
Some Mercedes models can be tampered with by removing the rear license plate light and plugging a charged battery into its wires.
Nissan hides the connectors under the fog light plafond.
BMW hides the emergency terminal in the underbody. By using it, you get an open car and a bottom cleaning in addition.
You need to read the car’s manual beforehand so you know all its “tricks.” Otherwise, you will have to apply current to less adapted for such purposes.
To the generator
This method is absolutely harmless for the car, but requires some effort. In order to power the alarm system in this way, you need to have a set of tools. Let’s list them.
Any battery with a voltage of 12 volts: another battery, a car Power Bank, or even a battery from a screwdriver.
Wire or cable with a cross section of 2 mm² or more.
Something you can lie down on without getting your clothes dirty. You’ll have to work under the car.
When everything is ready, proceed in this sequence.
Raise the front of the car with a jack.
Install the struts. This is a safety requirement. Bricks to put under the wheels will do.
Now lie down under the car, and remove the engine protection.
With a long wire, connect the positive terminal of the external battery to the alternator terminal that the “+” from the battery goes to. This can be identified by its color, it has a red wire going to it.
Attach the negative contact to the “ground” – any unpainted part of the car. The nut fixing the wheel will do.
Done. Press the button on the remote, the doors will open. All that remains is to wash the clothes.
It is better to take aluminum wire, not copper. It will be more convenient to work. Aluminum holds its shape well, but copper can bend under its own weight.
To make the task easier, you can apply power to the starter. The sequence of operations does not differ much.
Lift the front of the vehicle and place a prop.
Attach the “plus” from the external battery to the red starter wire. If there are two, attach to the thicker one. The thin wire goes to the retractor relay, you don’t need it.
The “minus” goes to the mass.
That’s it, press the remote. The car will open.
Instead of wire it’s better to take an insulated electrical cable. You have to strip the ends to make a good electrical contact. If you take the wire, make sure it doesn’t touch anything. Otherwise the current will go to “mass” and you will be left with a closed car and discharged external battery.
It is difficult and dirty work to connect to the generator. Besides it is dangerous, because it is easy to catch a cold lying on the ground. Especially in winter. In such conditions, it is better to do it in a different way.
On a discharged battery
The purpose of this method is to raise the hood by 5-10 mm. To do this you will need a special pad with a pear, which is sold in auto stores. The price is about 100 rubles.
To power the regular battery, proceed as follows.
In the corner where the battery is located, slip the cushion into the gap between the hood and the body.
Inflate it with air.
Bend a 2mm² wire with a hook, or, scientifically speaking, in the form of an integral. Place it on the positive terminal of the battery.
Connect it to the + of the external battery.
Connect the “-” from the donor battery to the “ground”. Suitable unpainted section of the body.
You will now be able to open the doors with the key fob.
This method will not hurt the car since the metal hood is flexible. A small pad will not be able to deform it. After you remove it, the hood will return to its original position.
Instead of a special cushion, a cuff from a tonometer will do. Only wrap it with a cloth, for greater strength. If you have nothing at all, make a wedge of wood and hammer it into the gap. A crude method, but it can help out in a difficult situation.
Experienced masters connect external battery to any consumer: headlights, turn signals, license plate illumination. The trouble is that it does not always work. But if you decide to try to do so, check the polarity of the consumer with a multimeter before connecting the battery. Otherwise there will be problems with electrics.
And then open the doors with the remote, open the hood, remove the battery and put it on charge or replace it. This is not a problem, because the most difficult task is to get inside the car.
How do you get into the cabin or under the hood?
Protective cover on the battery, dirt after off-road trips, oxidized contacts, age and general condition of the car – not a complete list of things that can prevent you from making everything beautiful. And if you have made a lot of attempts to reach the contacts, and the doors still do not open, you can go to the “mechanical” ways to get into the cabin.
Important! Before you apply them, find your passport and car ownership documents. Otherwise, vigilant citizens will call the police, and trouble will happen.
There are different ways to break into a locked car. Most of them require a wire. Make sure there are no sharp edges on it, otherwise there is a risk of damaging the paintwork.
Using a wire.
Not a bad way to go if there is a gap between the door frame and the glass. For example, you left it to air out the cabin in the hot summer. Or if you can slightly lower the glass with your hands when the window elevator mechanism is backlash.
Will need a flexible wire, fishing line or string with a length not less than the height of the door. And luck. Act as follows.
Tie a loop on the wire.
Slip it through the gap between the frame and the glass.
Hook the hinge to the door handle. The problem is that you can’t see it, so you have to guess.
To avoid difficulties, try pulling the “tongue” of the catch. You can see it through the glass.
Pull the string with light tugs. The doors will open.
Have patience, it will not work at the first attempt.
If there is only a rigid wire, for example, a bicycle spoke, then use it.
Bend the end of the spoke into a hook.
In the area of the door lock button, remove the window seal with a screwdriver.
Slip the wire through the slot, hook the button’s pull rod. The door is open.
Here, as in the first case, it is important not to lose patience.
Bending the door
If the glass is fully raised, and you can not remove the seal, you can try to bend the corner of the door. Then you will have access to the lock button.
Proceed as follows.
In a gap between the door and the body slip inflatable cushion.
If it is not available, then hammer a wooden wedge or a large screwdriver. Wrap a rag around them to avoid scratching the paint.
When a gap appears, pick up the opening handle or door latch with string or wire.
It is best to unbend the door at the top corner. This will increase the console, and it will be easier to work. A gap of 5-10 mm is enough for the job.
Using a rope
On most cars, the cable that holds the hood goes under the left fender from the lock to the cabin. This can be used.
Bend a hook on the wire.
Hook the wire around the radiator and left headlight with the hook.
Pull it with gentle tugs.
If there is no wire, you can use a screwdriver. You will have to grip it.
Using an iron ruler
Previously, this method was used by robbers to steal VAZ 2101-07 and other outdated models. If you have such a car, it can be opened with a long metal ruler.
On the contour of the door, subtract 10-15 cm away from the lock rod.
At this point, remove some of the sealing rubber.
Insert the ruler into the gap. It should be inside the door.
Hook it and push it out with the button. You should have backed off 15 cm to get a lever with a fulcrum on the seal.
This method is suitable if your car is over 20 years old. In newer models, the door handle mechanism is hidden deeper and protected by a mesh.
Of course, nobody cancels the rough methods of car’s opening.
Break the side window. Choose one that is easier to replace. Side windows in the racks are no good: the glass on them, though small, but rare and expensive. Keep in mind that splinters will fly into the interior, so you need dry cleaning. Or, if you are not lucky, the front panel will be repainted.
Drill the locks with a drill. Effective, but will require expensive replacement of all locks and their keys.
Never break the rear window, or the buyer will have questions at resale. And if the windshield is cracked, better break it, you’ll have to replace it anyway.
If you can not open the locks yourself, and you do not want to damage the car, then contact a professional. The call costs 3,000-5,000 rubles, and you will have to wait for the arrival of 30-40 minutes. During this time, prepare a passport and a document confirming the ownership of the car. And the experts will make everything clean.
When you change the battery, take a test drive of 10-15 km. This way the engine and automatic transmission control systems will re-adapt to your driving style, and the car will drive like before. And in the future, try not to allow the battery to be completely discharged.
But it is necessary to find the source of the problem. It may be the battery, wiring or long idle time. In the latter case, remove the battery before parking to avoid such situations.