Mercedes Central Locking System Not Working (Fixed)

The central Locking System controls all the locks in Mercedes-Benz. The most common problems that affect the central locking system are blown fuse, or the batteries in the key fob may need to be replaced from time to time. Resetting the central lock system in a Mercedes-Benz takes less than 2 minutes.

Common Central Locking System Issues

Like any other system in your Mercedes, the central Locking System is prone to issues, faults, and glitches.

The Key Fob Won’t Unlock Or Lock The Doors Or Open The Trunk

If the key fob isn’t working as it usually does or if there is a delay in the signal or if you have to press the buttons on the key fob several times before the vehicle finally unlocks or locks, the likeliest explanation is that the batteries are old and need replacing. 

It could also be that the wiring in the key fob short-circuited because it fell into some liquid. You will not need a mechanic to replace the batteries in the key fob. 

Just head to any hardware store and ask for key fob batteries. After you buy the batteries, you can replace them right there in the store.

The Central Locking Fuse Blew Out

In your Mercedes-Benz vehicle, there is a fuse box that holds all the fuses for the vehicle. The central locking system has a fuse and that fuse may occasionally burn out over several years of use. 

If you can locate the fuse box in your Mercedes-Benz, then you open the fuse box yourself and replace the fuse. You will need to use your vehicle manual to locate the correct fuse that connects to the central locking system. There are over 30 fuses in a vehicle’s fuse box, so just don’t start pulling out fuses.

What Is The Central Locking System?

When you press the lock button on your key fob, it’s in the signal to Mercedes, and all the locks in the vehicle lock it once. The driver’s door opens when you press the button one time. 

When you press the unlock button twice quickly, it will unlock every door around the vehicle. The reason the key fob can unlock every day and the truck is that the manufacturer connected it to the central locking system. The central locking system, of course, controls all the locks in a vehicle. 

Any vehicle that has locks has a central locking system. It is the same system that automatically locks all the doors in your Mercedes when the vehicle’s doors are closed and then the driver’s door closes.

For certain vehicles, placing the key into the keyhole of the driver’s door and turning it twice unlocks the door on the other side. The unique features and commands of the central locking system differ from brand to brand and model to model. 

Some vehicles even let the driver open all the doors and then Mercedes if the driver’s smartphone is connected to the Mercedes. 

Are we living in the future or what?!

The central locking system also controls the lock in the trunk. So when you use the key fob to open the trunk, the Locking system will receive the signal from the key fob and unlock the black and whole system from the inside.

Auto Lock Feature

Human beings are forgetful. Sometimes we walk into rooms to get something and then when we’re in that room, we no longer remember what we came into the room to get. 

Manufacturers know this and so they have set some of their Mercedes vehicles to lock the door when the driver and all the passengers exit the vehicle. The vehicle will automatically lock after 1 minute of no activity in or around the car.

How to reset your Mercedes Central locking system.

Before taking your Mercedes to a Mercedes-certified mechanic, you can reset the central Locking System yourself and see if that fixes any glitches or issues. You will not need any special equipment to reset the central locking system. 

Here’s what you need to do:

Unlock the two front doors, the driver’s door and the driver’s passenger door. Then, lock the two back rear doors. Then, press and hold down the lock button on the key fob for 6 seconds. 

You will know you performed the reset correctly when you can open one of the back doors on either side of the vehicle, despite pressing the lock button on the key fob.

If resetting the central Locking System did not fix any of the glitches, then you will have to take your Mercedes to a mechanic. The mechanic will assess the issues with the central Locking System and fix any software issues or mechanical issues. 

Our research found that mechanics will want to replace the central Locking System rather than repair it. Repairing is time-consuming and does not make that much money. The cost to replace a Locking System can be as high as $600.

If the central locking system does not work because of a software glitch, then fixing the software glitch should not cost more than $200.


The central Locking System is the system in a vehicle that controls all of the locks in and around the car, including the trunk and the key fob. If the key fob’s batteries are older and damaged, you may have to press the button repeatedly before the vehicle finally registers the signal. If you have a bit of patience, you can replace the central locking fuse yourself. You can download a manual from the Mercedes-Benz website if you don’t have your original manual. Replacing a locking system can be as high as $600 and your mechanic may not want to repair it.

  • Eric Williams

    I'm the founder of Daily Car Tips. I wrote articles in the automotive industry for more than 10 years, published in USA and Europe. I love sharing my knowledge and insights with fellow enthusiasts. Join me on this journey as we explore the exciting world of cars together!

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