Free Sample
The Complete Handbook of Vehicle Door Locks & Locking Systems
A practical reference for installers, fleet managers, security professionals, and serious owners: how to specify, fit, maintain, and repair vehicle door locking systems that actually keep working.
by Alumigogo Books
Chapter 1: Understanding Vehicle Door Locks & Locking Systems
What You Are Actually Working With
Vehicle door locks are not a single part. A door lock is a system of interdependent components that typically spans from the outside handle to the latch mechanism inside the door, and then often continues as an electrical circuit through the body of the vehicle. Understanding this system starts with understanding its parts.
The part most people point to when they say "door lock" is the exterior key cylinder. That is the visible face of a much larger assembly. Behind the cylinder is a linkage or a cable that connects to the latch mechanism itself. The latch is the core mechanical unit. It is what does the actual work of holding the door closed and releasing it. The latch also has several states beyond just locked and unlocked. It has a primary position that engages the striker on the body to keep the door fully shut, and it has a secondary or safety position that catches the door if it was not closed with enough force. This secondary position is why a door that is slightly ajar can still appear closed but will not actually latch. Handle mechanisms on the inside and outside, interior lock buttons or knobs, and in many modern vehicles, a small electric motor called a power lock actuator, all work together to move the latch into its various positions.
When you turn a key in the cylinder, you are rotating a