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How Does a Car Door Lock Work? – Car Lock Mechanism

Fact checked by Teddy B.Miller

how does a car door lock work

How does a car door lock work? A car door lock works by automatically locking the door when it is closed, and it can only be disabled by using the remote, door knob, and the car door lock button inside the car itself.

Different types of car door locks may have different parts. Read below to learn more.

How Car Door Locks Work


As evident from its name, a car door lock secures the entry to your car so that you can keep your vehicle and belongings safe.

Before diving into the actual mechanism of this device, here are some general parts of a car door lock that you have to know:

  • Door handle – Also called a handle strip, a door handle is manually operated to unlock the car door, and is usually attached to the inside and outside part of the car door.
  • Door lock – If we look at the anatomy of a car door, the door lock is installed in the inside part of the door and contains a latch and an actuator.
  • Door lock buttons – Door lock buttons are situated on the inside part of the car door lock, where the driver can easily access them to control the windows and doors of the car.
  • Remote control – In modern cars (electric or otherwise), keys are replaced with remote controls, which are used to remotely lock and unlock the car.
  • Keys – Keys are essential to a manual car door lock mechanism and must be inserted into the lock itself. They have detents that match the recess of the lock to force the door open.

So, how do automatic car door locks work? The self locking door latch is divided into two parts — the “male” part on the vehicle frame and the “female” part on the edge of the car door.

According to the car door lock mechanism diagram, when the door is closed, the hooks on the “female” part of the automobile door latch fold around the “male” part of the car door latch. That is why when you try to open the vehicle without operating the handle, the car door will not budge.

Your car door handle mechanism is mainly driven by the actuator.

The actuator is connected to a rod that moves the latch up and down, thereby opening or closing the door. Actuators are motors that operate using battery power, and can be activated using your key fob.

For automatic door locking system, remote controls are used. So how do they work? This the process your remote control and car go through, from pushing a button to having your door open:

  1. Pressing the lock or unlock button on your remote control enables the Central Processing Unit or CPU inside your remote.
  2. Based on the button you just pressed, the CPU will send data through electronic signals to the built-in radio frequency transmitter.
  3. The transmitter will release the data stream that contains the command to lock or unlock the door.
  4. The receiver inside your car’s remote keyless system will process the signal transmitted. From then, the signal will go to the CPU and then the command is carried out.

There are two types of keyless entries – passive and active. The former doesn’t require you to take the key out while the latter does. The reason is passive systems can detect a key fob whenever it’s close by and automatically communicate with it.

How to Fix a Car Door Lock Mechanism?

Having a car door lock broken or lock mechanism stuck would prove to be a hassle, especially when you are in a hurry. Fortunately for you, there is something you can do to fix it.

Follow these steps to fix the locking mechanism for car door:

  • From the inside of your car, take your door panel off. Do this by removing the screws off the door lock.



  • Remove the panels of the car door with your screwdriver.


  • After unscrewing, remove the inner handle cover from the door lock.
  • Take the door panel from the bottom and remove it by carefully raising it.




  • Take a razor and cut the plastic sheeting between the door panel and the door.
  • Locate the bolts inside the door handle.


  • Remove the bolts with a wrench and a socket extension.
  • After removing the bolts, the door handle will pop out of the outer side of the door.
  • The lock assembly would also come out.
  • If either one or both of the lock assembly and the door handle is broken, you might want to replace them with the same model.
  • Slide the lock assembly in first and attach it to the locking arm.



  • Put the handle back. Ask for assistance to steady the handle while you bolt it on the inside part of the door.
  • Put back the bolts with your wrench and socket extension.

Now, your inside car door lock is fixed and ready to use!



Protecting your family and valuables inside the car from unwanted guests should be one of your priorities when parking or traveling. Even if you already have a car alarm, you can never be too careful.

Knowing the answer to the question “how does a car door lock work?” will help you take advantage of the built-in security measures of your car. It would also tell you what needs to be repaired or what is lacking.

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