The lock is set from inside the door.
How does door lock works.
Doors with a twisted tab lock are still easy to get past even if that tab is set to lock these locks appear on the handle of a door when either facing laterally or vertically the door will be locked or unlocked.
The lock mechanism may not work simply because the lock is dirty or dry and needs to be lubricated with graphite do not use any type of oil because this will gum up the works.
Some vehicles equipped with remote keyless entry will find the key fob operates the driver s door lock even while the door lock relay is defective.
How door locks work.
For serious lock problems it is usually best to call a locksmith or to replace the lock.
A key is necessary to release the tang.
The cam then releases a spring which shoots the tang forward securing the door to the wall.
The key turns the cylinder which in turn turns something called a cam.
Once the key is removed the spring will automatically push the latch back out.