Central Locking Motor – Buying Guide

Central locking motor part

Close-up view of the casing for a central locking motor part

When you are looking to buy a central locking motor to replace your old one it is important to match up the part numbers to be sure it’s the correct one for your car. Get it right the first time – You do not want to purchase the wrong one and then go through the process of finding the correct one all over again.

At Your Car Spares Ltd  – What we test and look for!!!!

To test central locking motors we simply have to lock the doors using either the key fob or the door lock and then try to open the door to see if it has locked. If it is locked then we will unlock the doors  and check each door again. The most common problem with central locking motors is that they become unresponsive or one of the motors will do the opposite to the rest, for example it may lock when the others are unlocked or it may be unlocked when the others are locked.

You can use a multimeter to ensure that power is being sent to the motor otherwise it could be a problem in the circuit. We also listen out for any sounds with the locking motor. You should be able to hear your normal locking sound but sometimes you may hear a grinding or screeching noise which is a sign that the central locking motor could be on its way out.

Where to find the Part Number

The part number can be found on the plastic casing of the central locking motor , sometimes it may be on a label but usually it’s printed directly onto the motor.

Parts number for a Central Locking Motor

Where to find the parts number for a central locking motor

Parts number close-up view

Close up of a GM vehicle sample parts serial code

Locking motor

Parts number from different view

Serial code for the motor

How does a Central Locking Motor work?

The central locking system has 3 components and they are a key fob, a control module and an actuator. The fob is responsible for sending a coded signal through radio waves to the control module which then sends power to the actuators to either lock or unlock the door. A central locking system will either use a solenoid actuator or a motor actuator.  In a solenoid actuator there is an electromagnetic switch which will lock or unlock depending on which way the power is coming from.

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A motor actuator will have a rod connected to the door latch and another connected to the latch on the top of the door that tells you if the door is locked or unlocked. Inside is a set of gears that are powered by an electric motor and the last gear moves a rack and pinion gear set which in turn locks or unlocks the door. A rack and pinion gear set is a linear actuator which changes rotational (curved) motion into linear (straight) motion by using a circular pinion on the teeth of a bar or rack and as the pinion rotates it moves along the rack.

Locking motor piece

Locking motor piece

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