How Power Door Locks Work

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I took apart the door lock and latch mechanism from my Toyota Corolla to find out what's inside and how it works. I made a short video that I'd like to share with you all:


The door latch mechanism is held inside the door itself, and connects to the handles and key cylinder via actuator rods. Some vehicles use flexible cables:



Here's the latch removed, you can see on the right where the rods attach, and in the middle where the teeter/totter mechanism works to unlatch the door. Near the left side of the photo is the door lock actuator part.


What's interesting is how the door is "locked" - not by putting a physical lock through a hole the way you would the front door of your house, but by simply disabling the door handles, preventing them from triggering the unlatching mechanism!

The power door locking mechanism is fairly straight forward, a DC motor with a built in thermister drives a small gear train that turns the actuator lever:


Finally, there's the key tumbler, which is very similar to the one in the ignition. The little plates inside move up and down according to the jagged edges on the key. If they match, the key can turn!


And that's all the parts that go into making your power door locks work. Of course modern cars have more sensors and switches to detect the position of the key and lock to control things like the window, power door all unlock and alarm system.



Enjoy!
 
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