How to Change Mercedes Key Battery

These days, Mercedes provides you with a smart key fob to lock and unlock your car with. These little keys are powered by batteries, so you need to change them from time to time. In this short guide, we’ll show you all the steps to take.

Of course, there are different key models out there, so we’ve listed instructions for all the versions you might have.

Chrome Key (Most Recent Model)

There are actually two chrome keys circulating right now; one with a triangle panic button and one with a circular one. Here’s how you replace their batteries:

Triangle Panic Button

Look at the bottom of your fob and pull on the black tab. This will release the key from inside the fob.

Now, you will see there’s a gap in your fob, and one side is flat while the other almost dips inward a bit. Take the tip of the key and insert it into the flat side of the gap until you feel the case pop open.

The black case will pop open, and you can lift it all the way up and take out the small Mercedes key battery. Then, put your new battery in place - making sure the positive is facing you - and fit the black cover back on. Then, slide the key back inside fully, and you’re done!

Circle Panic Button

Slide the small black tab at the bottom of your fob while pulling the key out at the same time.

Insert the handle of the key into the groove on the flat side of the fob, right by the edge. Pull it inwards while pulling the whole case backwards.

You can now slide out both batteries and replace them with new ones, then slide the whole case back on and push the key back in.

Black Plastic Key Fob (Older Version)

Slide the small black tab at the bottom of this fob while simultaneously pulling out the key from inside.

Then, insert the key into the open groove from the side, with the long part of the key going into the very far side of the fob.

As you do this, pull up the part of the key fob with the black tab on, and a small battery casing will slide out.

There will be two batteries touching each other, so replace them - ensuring that the minus of the plus of one battery touches the minus of the other. Slide this small casing back into the fob, then put the key back inside.

First Model Smart Key Fob (Oldest Version)

The oldest version looks slightly different from the one that comes after it, but the Mercedes key battery replacement process is the same.

Pull the grey tab, take out the key, insert it into the groove from the side, then pull out the battery compartment. Replace your batteries and slide everything back into place.

There you have it, this is how you change a Mercedes key battery on all models of the smart key fob. It’s very easy to do, and once you’ve done it once or twice, you get the hang of it.

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