How to Replace a Battery in a Mercedes Key Fob

If you’re experiencing issues with your Mercedes key fob, like reduced signal strength or unresponsive buttons, it might be time for a battery replacement. Luckily, this is a simple task you can often handle yourself at home. This guide will walk you through the steps of How To Replace A Battery In A Mercedes Key Fob, saving you a trip to the dealership.

Identifying Your Mercedes Key Fob Type

Before you get started, it’s important to determine which type of key fob your Mercedes uses. There are two common types: the traditional “chrome” key fob and the newer “smart” key fob.

• Chrome Key Fob: This type features a chrome metal casing and a flip-out key.
• Smart Key Fob: This type is sleeker and has a black plastic casing with chrome accents. It often lacks a visible flip-out key.

The process for replacing the battery varies slightly depending on the key fob type.

Replacing the Battery in a Chrome Mercedes Key Fob

Here’s what you’ll need:

• A small flat-head screwdriver
• A new CR2025 battery

Step 1: Release the Emergency Key
Locate the small button or lever on the side of your key fob. Press or slide it to release the emergency key blade.

Step 2: Open the Key Fob
Insert the flat-head screwdriver into the slot exposed by removing the emergency key. Gently pry open the two halves of the key fob. You may hear a slight click when it disengages.

Step 3: Replace the Battery
Carefully remove the old battery. Note its position (+/- orientation) and insert the new CR2025 battery in the same way.

Step 4: Reassemble the Key Fob
Align the two halves of the key fob and press them together until you hear a click. Make sure it closes securely.

Step 5: Reinsert the Emergency Key
Slide the emergency key back into its slot until it locks in place.

Replacing the Battery in a Smart Mercedes Key Fob

Here’s what you’ll need:

• A small flat-head screwdriver (in some cases, you may need a small Torx screwdriver)
• A new CR2032 battery

Step 1: Open the Key Fob
On the back of your smart key fob, you’ll find a small panel or a release button.

• Panel: If there’s a panel, use your fingernail or the flat-head screwdriver to pry it open.
• Release Button: If there’s a button, press it to release the emergency key blade.

Step 2: Access the Battery Compartment
With the emergency key removed, you’ll see a slot where it was housed. Insert the flat-head screwdriver (or the appropriate Torx screwdriver) into this slot and gently twist to open the battery compartment.

Step 3: Replace the Battery
Carefully remove the old CR2032 battery, noting its position. Insert the new battery in the same orientation.

Step 4: Close the Battery Compartment
Align and press the battery compartment cover back into place. You should hear or feel it click shut.

Step 5: Reinsert the Emergency Key
Slide the emergency key back into its slot until it locks.

Testing Your Key Fob and Important Notes

Once you’ve replaced the battery, test all your key fob functions to make sure it’s working correctly.

• Important Notes:
  • Handle the battery with clean hands to avoid transferring oils that can shorten its lifespan.
  • Dispose of the old battery properly according to your local regulations.
  • If your key fob still doesn’t function correctly after a battery replacement, there might be other issues. In such cases, it’s best to consult a qualified Mercedes technician.

Replacing the battery in your Mercedes Key Fob is a straightforward process that can save you time and money. By following these steps, you can easily maintain your Key Fob’s functionality and ensure a smooth driving experience.