When a car central locking system works, it works like magic. All you have to do is push a button on your key fob and your car doors will lock or unlock automatically. Unfortunately, there are many electronics and moving parts involved, so it's possible to find your car's central locking system not working at some point in time.

A failing car central locking system might be due to a blown fuse, faulty solenoid, or electrical wiring issues. Lastly, the problem might not be with the central car locking system but the key fob instead. Key Fobs can become problematic, and their batteries will die eventually, both causing the same outcome.

As you read the following sections, you’ll discover the most common problems affecting your car central locking system. So, the next time you find your car locks not working, you’ll be able to troubleshoot and solve the problem without so much worrying.

How a Car Central Locking System Works

Firstly, let’s do a quick recap of how the central locking system works. When you understand how it works and the parts involved, understanding its problems becomes much more manageable.

Using the system begins with the car central locking remote (also referred to as the key fob). That remote will send a signal to the receiver connected to the Engine Control Unit (ECU) that coordinates the system’s functions.

From there, the ECU will then activate the solenoids in each door to lock or unlock the door simultaneously.

What Are the Most Common Causes of a Malfunctioning Car Central Locking System?

Now that you have a rough idea of how the car central locking system works, it’s much easier to learn why it might malfunction. Here, we’ll look at the top four reasons: key fob issues, blown fuse, a faulty solenoid, and wiring issues.

Key Fob Issues

Here’s a pro tip that applies to troubleshooting a car central locking system: always start with the most likely causes, which are often the easiest to fix. In this context, the most likely reason for your car locks not working is a problem with the key fob.

To recap, the key fob or car central locking remote is the device that sends signals to the system to do its job. These key fobs use tiny batteries that will eventually run out of charge. When that happens, your car locks won’t respond even when you use the key fob.

Besides dead batteries, it’s also possible that the remote itself is faulty. Perhaps the key fob has been in use for a long time, experienced plenty of wear and tear, or even fell into some water. All of these could cause the key fob to fail.

How to fix this: 

Start by opening and inspecting your key fob. You might find that the buttons are misaligned or that the battery may have come loose. If everything is in order, but it still won’t work, then your next step is to replace the battery in case it’s dead.

Suppose the car central locking remote still won’t work, then you might need to replace it. In many cases, you can get a locksmith to duplicate your key fob, and you’ll be on your way in no time. 

However, some brands and models require key fobs that you can only get directly from the manufacturer. You can usually order those through your local distributor, but be prepared to pay for it and wait days or longer for them to be ready.

Blown Fuse

Your car's central locking system is connected to the car’s overall electrical system. That means it has one or more fuses that are put in place to protect it from electrical damage. If that fuse has blown, you’ll find your car locks not working.

To troubleshoot this issue, look for your car’s fuse box and identify the fuse for your car's central locking system. Blown fuses will look and smell burnt or make a noise when you shake them close to your ear.

How to fix this: 

If this is the case, all you have to do is replace the blown fuse. Once the system has power again, you’ll be able to reset central locking and use it like normal again.

Faulty Solenoid

A solenoid is a component that converts electrical power into mechanical movement. In a car central locking system, the solenoid in each car door will activate and lock or unlock the door.

Here’s a sign that you have a faulty solenoid: if you find the locks not working on only one or two doors (instead of all of them failing at the same time), then the chances are that the solenoid on that door has failed.

How to fix this: 

The solenoid is hidden inside your door panel, so replacing it isn’t a simple DIY for novices. Instead, a qualified technician can help you take the door apart and replace the affected solenoid quickly.

Wiring Issues

Once you’ve ruled out all of the other possibilities, the last possibility to explore is problems with the central locking system's wiring. The system comprises several electrical components located in each car door, all interconnected with wires.

If those wires are broken or burnt at any point, the car central locking system will not work as it should.

How to fix this: 

This is another repair task that you might not want to take on as a DIY project at home. Not only is it labour-intensive, but it also involves working on your car’s electrical system.

The repair involves inspecting every inch of the wiring to locate the problem. Then, the section that’s broken or burnt will need to be repaired and spliced together.

Learn More about Car Troubleshooting

To learn how to solve common problems like a car central locking system not working, check out the blog at Carpart.com.au. There, you’ll see plenty of guides for many other issues faced by everyday drivers in Australia and beyond!

By Ray Hasbollah