How Does a Car Door Lock Work (Guide)

Cars have all sorts of door locks ranging from Standard Key Entry to Keyless Entry door locks. The type of lock depends on the model and features of your car, but most have Electronic Locks.

In general, the working mechanism of a car door locking system is quite simple. The latch rods exert a force on the lock or open switch located at the back of a car’s door. The exerted force flips a pair of jaws on the door lock. Then the jaws are released. A car door lock is a mechanical device that locks and unlocks the car door.

How the Actuator Works

The actuator is located on the inside part of the car door lock, below the latch. A rod links the actuator to the latch, and another rod links the latch to the knob. This knob sticks up on the top of the door.

side car lock button
Video | speedkar99

The actuator lifts the latch and connects with the door handle (on the outside part of the car). This process opens the car door. When the actuator is lowered, the handle (on the outside part of the door) gets disconnected from the latch. Thus, the door closes/locks.

The actuator slides the metal hook in either left or right directions. The hook is vertical so it can move downwards and upwards. The hook movement moves the doorknob motion, that is, pulls or pushes. The actuator has a small electric motor that spins a series of spur gears. The last gear moves the rack-and-pinion gear set that is linked to the actuator rod. The motor’s rotational motion is turned to linear motion by the rack system. This linear motion turns the door lock. (1)

mechanic inspecting the car door lock
Video | speedkar99

A centrifugal clutch is connected to the gear to hinder the movement of the motor when you move the latch. On spinning the gear (by the motor), the clutch jerks out. This action locks the small metal gear to the large plastic gear hence the motor drives the latch.

Computer-controlled Automatic Locks

Electronic door locks have similar features, whether they are single or multi-purpose. Below are the components and features of electronic car doors:

  • A door lock or a latch
  • An actuator
  • The actuator rods
  • They are activated by a radio

Computer-controlled locks use radio signals to start open door lock and unlock modes. The computerized system passes computer programming to the key controller computer. The key controller reads the instructions and then performs a proper system command – locking and unlocking the door. The key controller module also performs the following. (2)

  • Automatic security measures
  • Opening the trunk lid
  • It can start the car remotely
  • Lowering the car windows
  • Stop the ignition

How to Open and Close the Door in the Right Way

Don’t overstretch the car door connectors and hinges. Follow these steps.

  1. Verify the status of your doors and windows. Make sure you check the car doors and windows before you attempt to unlock them.
  2. Press the unlock button on the inside part of your car. Besides, you may use a key or a computerized remote control to open your car door. Make sure you hold on to the car door while it opens to prevent it from overstretching.

Winding Up

You need to close your door properly, do not slam it against the sealing lining. Slamming the door causes wear and tear. Just pull and push it carefully and keep your hand on it until the door is closed.

Take a look at some of our related articles below.

(1) movement –
(2) computer programming –

Video References


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About John Fox

ebbb364ee14268bd3b77496cab3d1d78?s=90&d=mm&r=gCertifications: Certified Alarm Technician (CAT)
Education: Denver Security Academy
Lives In: Denver Colorado

John Fox has worked as a security consultant in Denver for over 20 years.
With Safe Now, he's taken those two decades of experience and decided to share it to help people online make the right security decisions for their businesses and families.

John writes security tips and guides, product recommendations, and prevention guides.

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