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mercedes benz w203 rear trunk

How to manually open trunk of any Mercedes


Have you locked the keys inside the trunk of your Mercedes-Benz? Maybe your key fob isn’t working or car battery is dead and you are trying to unlock the trunk of your Mercedes-Benz. If your car battery is dead or the key fob remote has stopped working, you won’t be able to unlock your Mercedes-Benz or open the trunk.

In this article:

  • How to open Mercedes-Benz trunk when the battery is dead
  • How to unlock trunk when the key is not working
  • Keys locked in the trunk How to open Mercedes trunk.

How to manually unlock the trunk of a Mercedes-Benz

If your Mercedes battery has died, trunk switch or key fob remote aren’t working, you can use this method to unlock the trunk.

Step 1 

Remove the metal key from the key fob. You will need to slide the locking tab with your thumb and pull out the metal key.

Step 2

Insert the key into the trunk lock cylinder.

Step 3

Turn the key until you hear the trunk pop open.

Note: Avoid jump starting your Mercedes-Benz by connecting the jumper cables directly to the battery. Instead, use the positive jumper starter terminal located in the jumper cable.

How to open the trunk if trunk if the key isn’t working or keys are locked in the trunk.

What if you started replacing the battery in the trunk and you accidentally locked the keys inside the trunk. Now you are wondering how can I open the trunk? Here are a few similar scenarios.

  • The car battery has died and the battery is in the trunk.
  • You locked the keys in the trunk and the battery is dead.
  • Or you tried to manually unlock the trunk but can’t turn the key manually.

So what do you do? Luckily, there is another way to power up your Mercedes-Benz.


Get a locksmith to open one of the doors then follow these steps.

Step 1

Release hood by pulling on the hood release lever on the side of the dashboard.

Next, open the hood. how to open mercedes trunk

Step 2

All Mercedes-Benz model year 2000 and newer have a jump start terminal inside the engine bay. Regardless if the battery is in the trunk or under the rear seat. Locate the positive jump starting terminal. This is how the positive jump start terminal looks on an E-Class W210how to power your mercedes if you can't get inside battery dead

Here is another example. battery positive termnial

Step 3

Connect a jump box positive terminal to the positive terminal and the negative jumper cable to a ground point or frame. Alternativly instead of a jumper cable how to safely jump start a mercedes benz e c s gl ml cls clk class

Now you can press the Lock/Unlock buttons on your Mercedes-Benz key fob remote to unlock the car or the trunk. You can even start the car this way.



  1. I am a AAA service tec and I recently had a call where a member had locked thier keys in the trunk of thier E350. I was able to succeed in opening the door, however they did not have the pass into the trunk through the back seat. I was unable to get the trunk open for them and they ended up paying an expensive tow bill to have the vehicle taken to a dealer to get the trunk unlocked. Is the any way that I can open the trunk after the security system is activated to avoid this situation in the future?

    • Good question. You will have to get through the back seat which would be a lot of work and you can’t really do on the side of the road. If your battery is dead or the car hasn’t locked, I would recommend connecting a 12-volt source under the hood at the post/neg terminal and that will power up your Mercedes.

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