Unlocking A Car Door With AA Battery. How? And Why You Shouldn’t Do That

ATTENTION! The method of unlocking the car with an AA battery is described purely for entertainment!!! Never try doing this in your vehicle because you may damage expensive electronics!!!

Unlocking a car door with a AA battery is a trick that has been popularized through TV shows and movies. They make it simple on TV but is it really possible to unlock a car door with an AA battery? And will it have any adverse effects on your car.

Though this method won't work on all types of car locks, you can indeed unlock a car door with a AA battery. It works by connecting the positive and negative ends of the battery with a wire and sending a small electric current through your door's locking mechanism. But doing so is not recommended as it could end up damaging your car's locking mechanism. 

• How Does It Work
• How To Unlock A Car With A AA Battery
• Why Shouldn't You Do So
• Other Viable Options

How Is It Possible To Unlock A Car Door With AA Battery?

When you use your key fob to unlock your car, it activates the central locking mechanism of your car locking or unlocking all the doors at once. The way this central locking system works is pretty simple. This central locking system relies on an electronic module that is located within the car. When you press the button on your key fob, the signal is received by this module, and it sends a signal to the central locking mechanism to unlock all the doors. 

The locking mechanism in your car is basically an electrical circuit that consists of wires, switches, and actuators. And just like any other electrical circuit, this too needs a power source, and generally, your car's battery is the power source for your locking mechanism. When you use a AA battery to unlock a car door, you bypass this power source with an alternate power source which is the AA battery. By making a temporary connection with the positive end of the AA battery and the locking mechanism in your car door, you are able to power the central locking system without your car's battery. 

When the AA battery is connected to the locking mechanism, it creates a power surge within the circuit. This power surge mimics the power surge that would come through your car's battery when you use a keyfob to unlock the door. If everything goes well, the actuators in the circuit will be activated unlocking your car doors. 

How To Unlock A Car Door With AA Battery?

Now that you know how exactly unlocking a car door with a AA battery works, let us look at the procedure behind unlocking a car door with a AA battery. 

In theory, unlocking your car with a AA battery requires you to connect the positive and negative terminals of the battery with their corresponding terminals on your car door's lock. 

So, for this to work you'll obviously need a AA battery. Preferably a fresh one with enough juice. Even something bigger like a 9V battery should work just fine. Along with the battery, in order to transfer the current you'll need a couple of pieces of wire. 

Now connect one piece of wire to the positive end of the battery and insert the other end into the corresponding terminal of the locking mechanism. This can be done by inserting the other end of the wire into the keyhole. Now with another piece of wire, connect one end to the negative end of the battery and connect it to the other end of the locking mechanism. 

This should send a surge of current through the locking mechanism and unlock your car.

How Likely Is This To Work?

In theory, unlocking a car door with a AA battery should work every single time. As mentioned earlier, it mimics the signal sent to the actuator unlocking your door. But it is not as simple as it sounds. 

Car manufacturers spend hundreds of thousands of dollars developing the security system of their vehicles. So these advanced security systems are not easily bypassed. Though the theory suggests that this method of using a AA battery to unlock a car door should work, it is not applicable to every model.

That being said, some owners have found success by following these exact same steps and unlocking their car doors with a AA battery. If you scour through the forums and the internet, you'll notice that more often than not, when this technique works, it works with older vehicles. Rarely does this method ever work with vehicles manufactured in the 2010s or newer. 

Why Shouldn't You Unlock A Car Door With A AA Battery?

Whether it works or not, even trying to unlock your car door with a AA battery is not recommended. Whether you successfully unlock your door or not, by following this method you'll be sending an electrical current through your locking mechanism. 

1) You Could End Up Damaging Your Locks

First off inserting a wire inside the locking mechanism is not going to end well. Attempting to manipulate the locking mechanism with a wire could end up damaging the locking mechanism itself. If you end up using more force than necessary, you could end up damaging the internal mechanism.

The next thing to worry about is the electrical current itself. Your car's battery doesn't send a huge current when unlocking your door. When you are trying to bypass the locking mechanism with a AA battery, you are required to send a relatively larger current through the circuit. This could end up frying the circuit.

So, when using a AA battery to unlock your car door, you are risking your entire locking mechanism. Even by attempting this method, you could damage your locking mechanism. Once damaged, even your key or keyfob will be rendered useless.

2) You Could End Up Tripping The Alarm

Many cars have built-in security systems to restrict unauthorized entries into the vehicle. And as you might already know, using a AA battery to bypass the locking mechanism is not exactly a legitimate mode of entry. Even though you own the vehicle, the car doesn't know that it is you who is trying to break into the car. So, once the security system detects that you are trying to bypass the locks, the alarm will go off.

This'll be followed by loud sirens and flashing lights, drawing unwanted attention to you. You could even end up dragging the law by trying to unlock your car door with a AA battery.

3) Damaging Your Electronics

When you are sending a surge of current, damaging your electronics is definitely a possibility. Connecting the wires to the wrong terminals, or sending too much current could end damaging fuses, sensors, or any other electrical components in your car. This could lead to costly repairs. 

Other Methods You Could Use To Get Your Doors Unlocked?

Other than unlocking a car door with a AA battery, there are plenty of other more safe and reliable methods to get your car door unlocked.

1) Look For A Spare Key

This is the best and easiest way to get your door unlocked if you've lost your key. If you have a spare key available with a friend, or family member or stored in a safe place, your best bet is to retrieve it and get your door unlocked. This way you wouldn't have to mess with the locking mechanism and risk damaging it. 

2) Using A Shoelace Or A Coat Hanger

This is a simple and effective method if you are locked out of the car. But for this to work, you need to have an older car with a traditional-style pull-up lock button. These types of locks have a lever that needs to be pulled up in order to unlock the car. 

If this lock is present in your car, you can simply unlock your door with a shoelace. Tie a slip knot with a thin firm shoelace and squeeze it through your window. Slowly manure it so that the knot works its way over the lock. Once positioned, tighten the knot and pull up unlocking the day.

The coat hanger works the same way, but instead of pulling the knob, you go deeper into the locking mechanism. But the basics are still the same. 

3) Call For Help

If you are looking to get into your car without risking damaging your lock, you should contact a locksmith. But you should be aware this could cost a pretty penny. 

Another option is to call roadside assistance. With some AAA membership plans, you get a free lockout service every year. So, if you have a roadside assistance plan, you can get into your car for free. Plus, their services are available around the clock. 

Conclusion

If you are locked out of your car, unlocking your car door with a AA battery is an option. But this is not exactly a reliable nor recommended method. Though this is known to work, by attempting to unlock your car door with a AA battery you are risking crippling your locking mechanism. If you are locked out of your car, your best bet is to call for support or look for a spare key.