How Your Car’s Power Locks Work?

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Cars nowadays come with central lock system and automatic power locks which are very convenient, but how do they work?

Most car doors are unlocked by either a key fob or a remote and by pressing a button it will unlock.

The main Parts involved :

Body Control Module (BCM)

This is the brain of the system which is receiving signals from different sources and controlling different car functions like locks, lights and alarms.

Key Fob & Interior Switch

These initiate the locking and unlocking commands.


This is a small electric motor located inside each door and it converts electrical signals from the BCM to lock or unlock the door.

The Process Behind Your Car Power Locks:

  • Pressing the lock button on your key fob.

  • The signal is received by the BCM.

  • The BCM analyzing the signal and sends a specific electrical current to the actuators in each door.

  • The actuator receives the current and its tiny motor spins.

  • A gear system inside the actuator translates the motor spin into a linear movement (pushing or pulling) and depending on the direction of the current it moves the lock to lock or unlock the door.

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