Step by step guide on how automotive electric door locks work. This article pertains
to all vehicles.
Step 1 - Power locks or electric locks allow the
doors of a vehicle to be locked or unlocked by a switch or automatically. Activated
by a switch or remotely these locks add convenience to the operation of the locks.
A key fob or remote is used to operate these locks from a distance away from the
vehicle while illuminating the interior lights for safety.
Electric Door Lock
Step 2 - Occasionally the door lock will close
while the door is still open. When this happens follow this
door wont close repair guide
Door Lock Closed
System components include; lock actuator, switch, wiring harness and a circuit
breaker. Voltage is sent to the actuator by using a control switch and relay which
is connected to a power source and ground circuit. This simple electrical system
is protected by a circuit breaker than when heated will cutoff electrical power
until cool. Once cooled the breaker will reset allowing the door locks to operate.
The body computer can active the lock control relay when certain criteria is achieved
such as driving for a period of time, the locks will automatically engage as a safety
measure. A door lock actuator is located inside the door usually mounted in the
lower part of the door near the latch, or it is incorporated into the latch itself.
Actuators are constructed in one of two ways, either they are a simple solenoid
which are common among older vehicles, or they are a combination of an electric
motor and gear set which moves a lock control mechanism.
Written by Ken Lavacot Co-Founder and CEO of 2CarPros.com 35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.
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Article first published 2009-08-25 (Updated 2015-01-07)