How to Replace a Mercedes Key Fob Battery * bigfinish.com

When your Mercedes-Benz key fob’s battery starts to die, you may notice that the buttons don’t respond as well as they used to, or the range for locking and unlocking the car decreases. Replacing the battery in your key fob is a quick and easy process that you can do yourself, saving you a trip to the dealership. In this article, we’ll provide step-by-step instructions on how to replace the Mercedes key fob battery, along with helpful tips and troubleshooting advice.

The first step is to locate the battery compartment on your Mercedes key fob. In most cases, the battery compartment is located on the back or side of the fob. Once you’ve located the battery compartment, you’ll need to use a small screwdriver or coin to pry it open. Be careful not to damage the battery compartment or the key fob itself. Once you’ve opened the battery compartment, you’ll see the old battery. Remove the old battery and insert the new battery into the compartment, making sure that the positive (+) and negative (-) terminals are facing the correct way.

After you’ve inserted the new battery, close the battery compartment and test the key fob to make sure it’s working properly. If the key fob is not working, check to make sure that the battery is inserted correctly and that the battery terminals are clean. If the key fob is still not working, you may need to replace the battery again or contact a qualified mechanic or locksmith for assistance.

Required Tools and Materials

Replacing the battery in a Mercedes key fob is a straightforward task that can be completed with a few simple tools and materials. Here’s a detailed breakdown of what you’ll need:

Tools:

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Materials:

Tool	Purpose
Small flathead screwdriver	To open the key fob housing
Phillips head screwdriver	To remove the battery cover
Anti-static wrist strap	To protect the key fob’s delicate electronics from electrostatic discharge

Material	Purpose
CR2025 battery	The replacement battery for the key fob

Locating the Key Fob Battery

To replace the battery in your Mercedes key fob, you’ll first need to locate it. The battery is typically housed in a small compartment on the back or side of the fob. To open the compartment, you may need to use a small screwdriver or a key. Once the compartment is open, you should see a small, round battery.

Identifying the Correct Battery

There are several different types of batteries that can be used in Mercedes key fobs. The most common type is the CR2025 battery. However, some fobs may use a CR2032 or CR2016 battery instead. To determine which type of battery your fob uses, consult your owner’s manual or look for the battery type printed on the back of the fob.

The following table provides a list of the battery types used in different Mercedes key fobs:

Key Fob Model	Battery Type
A-Class (W176)	CR2025
C-Class (W205)	CR2032
E-Class (W213)	CR2025
GLC-Class (X253)	CR2016
GLE-Class (W166)	CR2025

Removing the Old Battery

Once you’ve established the type of battery needed, follow these steps to replace it:

1. Remove the key blade from the case by pressing the release button and pulling it out (for models without a physical key, this step is not necessary).

2. Locate the small release latch or button on the back of the key fob; it may be a small protrusion or a button with a Mercedes logo. Press or slide the release to open the case.

3. Carefully remove the old battery from the designated compartment within the key fob. Take note of its orientation and position within the compartment, as the new battery must be inserted in the same way to ensure proper functionality.

Inserting the New Battery

To insert the new battery, you’ll need to begin by opening the remote key’s case using a small screwdriver or flathead tool to pry it open. Inside, you’ll find the battery. It will normally be held in place by a small clip or bracket. Use the tool to gently remove the old battery and replace it with the new one, making sure to place it in the correct orientation.

Check Battery Orientation

Before inserting the new battery, double-check its orientation to ensure it aligns correctly with the contacts inside the remote. The positive (+) end of the battery should face outward, while the negative (-) end should face inward. Misalignment can prevent the remote from functioning properly.

Secure the Battery

Once the new battery is in place, use the clip or bracket to secure it. Ensure it’s held firmly to prevent rattling or dislodging, which could lead to intermittent functioning or complete failure of the remote.

Test the New Battery

After inserting the new battery, reassemble the remote and test its functionality. Press the various buttons on the remote to ensure they work as intended. If the remote still doesn’t respond, it may be necessary to reprogram it or seek professional assistance.

Reassembling the Key Fob

Step 1: Align the Key Blade

Once the battery is replaced, carefully align the key blade into its designated slot within the key fob housing. Ensure that it slots into place securely.

Step 2: Position the Back Cover

Next, carefully slide the back cover over the key fob housing. Ensure that the cover aligns correctly and fits snugly.

Step 3: Secure the Back Cover

Using firm pressure, press down on the back cover to secure it in place. You should hear a soft click or snap as it locks into position.

Step 4: Test the Key Fob

Take the key fob to your vehicle and test its functionality. Press the buttons to ensure they respond as expected. If all buttons work correctly, the key fob has been successfully reassembled.

Step 5: Additional Tips for Reassembling

Check for proper alignment: Ensure that all components are properly aligned before pressing them together. Misalignment can lead to damage or malfunction.
Use even pressure: Apply firm, even pressure when securing the back cover to prevent bending or cracking it.
Handle with care: Handle the key fob with care to avoid damaging its delicate components.
Refer to the user manual: If you encounter any difficulties during reassembly, consult the user manual for specific instructions and precautions.

Locate the Key Fob Battery

The battery is typically located inside the key fob, beneath a small cover. Use a small screwdriver or your fingernail to pry open the cover and expose the battery.

Remove the Old Battery

Use your fingers or tweezers to carefully remove the old battery from its compartment. Avoid touching the metal terminals on the battery to prevent short circuits.

Insert the New Battery

Insert the new battery into the compartment, ensuring that the positive (+) side of the battery faces up. Press down on the battery to secure it in place.

Identifying the Correct Battery Type

Different Mercedes-Benz models and key fobs require different battery types. Refer to the owner’s manual or consult with a Mercedes-Benz service technician to determine the correct battery type for your specific vehicle and key fob.

Close the Key Fob

Snap the cover back onto the key fob, ensuring that it is properly aligned and secure. Most covers have an audible click when securely closed.

Pairing the Key Fob (if applicable)

Method 1: Automatic Pairing

For some Mercedes models, the key fob may automatically pair with the vehicle after the battery has been replaced. If this occurs, no further steps are necessary.

Method 2: Manual Pairing

If automatic pairing does not occur, you may need to manually pair the key fob with the vehicle. The specific pairing procedure varies depending on the vehicle model and year. Refer to your owner’s manual or consult with a Mercedes-Benz service technician for detailed instructions on manual pairing.

Battery Type	Mercedes Model	Key Fob Type
CR2025	C-Class (2015-2021)	3-button
CR2032	E-Class (2017-2023)	5-button
CR2450	S-Class (2018-2025)	Smart Key

Remove the Key from the Fob

To gain access to the battery compartment, the physical key needs to be removed from the fob. Refer to your vehicle’s manual for specific instructions on how to detach the key, as the mechanism may vary depending on the Mercedes model.

Locate the Battery Compartment

Once the key is removed, identify the battery compartment on the back or bottom of the fob. It’s typically secured by a small screw or a snap-on cover.

Open the Battery Compartment

Using a small screwdriver or a sharp object, gently pry open the battery compartment. Take care not to damage the components inside.

Replace the Battery

Remove the old battery and replace it with a new one of the same type (typically a CR2025 or CR2032). Ensure the positive (+) side of the battery faces up.

Close the Battery Compartment

Secure the battery compartment by tightening the screw or snapping the cover back into place.

Test the Fob

Insert the key back into the fob and press any button to test its functionality. If the fob is working correctly, the LED indicator should light up or the car should respond to the commands.

Troubleshooting Common Issues

The Fob Doesn’t Work After Replacing the Battery

1. Incorrect Battery Type: Verify that you have installed the correct battery type (CR2025 or CR2032).
2. Battery Not Properly Installed: Ensure the battery is inserted correctly with the positive (+) side facing up.
3. Faulty Battery: Replace the battery with a new one, as the old battery may be defective.
4. Dirty Contacts: Clean the metal contacts on the battery and the fob using a cotton swab and rubbing alcohol.
5. Damaged Fob Circuit Board: If the fob has been subjected to moisture or physical damage, the circuit board may need to be replaced.
6. Transmitter Malfunction: The fob’s transmitter may have failed, requiring a visit to the dealership or a qualified mechanic.
7. Interference from Other Devices: Move away from any potential sources of electromagnetic interference, such as other key fobs or electronic devices, and try testing the fob again.

Safety Precautions

Before attempting to replace your Mercedes key fob battery, it’s crucial to adhere to the following safety precautions:

1. Park in a Safe Location

Ensure your Mercedes is parked safely in a level and secure area to prevent accidents.

2. Turn Off Ignition

Completely turn off the ignition and remove the key from the ignition switch.

3. Gather Tools

Collect the necessary tools: a small screwdriver (Phillips or flathead), a new CR2025 or CR2032 battery, and a soft cloth.

4. Disconnect Battery

If applicable, disconnect the negative terminal of the vehicle’s battery using the appropriate wrench or tool.

5. Wear Gloves

Consider wearing gloves to avoid potential exposure to battery acid.

6. Avoid Contact with Battery

Handle the battery carefully and avoid direct contact with its terminals.

7. Handle Key Fob with Care

Treat the key fob with care to prevent damage or malfunction.

8. Electrostatic Discharge (ESD) Precautions

To mitigate the risk of electrostatic discharge (ESD) that could damage electronic components, take the following steps:

Discharge any static electricity by touching a grounded metal object before handling the battery or key fob.
Handle components only by their edges or designated grip areas.
Avoid touching exposed contacts or circuit boards.
Use an anti-static wrist strap if available.
Work in a low-humidity environment to reduce the risk of ESD.
Store electronic components in anti-static bags when not in use.
If handling sensitive components such as circuit boards, consider using an ESD mat or grounded work surface.
Follow any additional ESD precautions recommended by the vehicle manufacturer or battery supplier.

Battery Type and Availability

Mercedes-Benz key fobs use CR2025 or CR2032 coin cell batteries. These batteries are commonly available at hardware stores, auto parts stores, and online retailers.

Battery Life

The battery life of a Mercedes-Benz key fob typically ranges from two to five years, depending on usage. Factors that can affect battery life include the frequency of use, weather conditions, and the condition of the fob.

Replacement Costs

The cost to replace the battery in a Mercedes-Benz key fob varies depending on the type of battery used and the location where the replacement is performed. Expect to pay between $5 and $30 for the battery and labor.

DIY Replacement Instructions

Materials You’ll Need:

CR2025 or CR2032 coin cell battery
Small flathead screwdriver

Step-by-Step Instructions:

Locate the battery compartment on the back of the key fob.
Use a small flathead screwdriver to gently pry open the battery compartment.
Remove the old battery and insert the new one with the positive (+) side facing up.
Close the battery compartment and secure it with the screwdriver.
Test the key fob to ensure it’s working correctly.

Dealer Replacement

If you’re not comfortable replacing the battery yourself, you can have it done at a Mercedes-Benz dealership. The dealership will typically charge a higher fee for this service than if you do it yourself.

Costs and Availability

Battery Type	Cost	Availability
CR2025	$5-$10	Widely available
CR2032	$5-$12	Widely available

Replace the Battery in Your Mercedes Key Fob

Replacing the battery in your Mercedes key fob is a simple task that can be done in a few minutes. Here are the steps you will need to follow:

Locate the small release button on the back of the key fob.
Press the button and pull the key fob apart.
Remove the old battery from the key fob.
Insert the new battery into the key fob, making sure that the positive and negative terminals are aligned correctly.
Snap the key fob back together.

Tips for Extending Battery Life

Here are a few tips to help you extend the battery life of your Mercedes key fob:

Avoid exposing the key fob to extreme temperatures.
Keep the key fob dry.
Do not press the buttons on the key fob unnecessarily.
Remove the battery from the key fob if you will not be using it for an extended period of time.
Use a lithium-ion battery in your key fob.
Make sure that the key fob is clean and free of debris.
Do not drop the key fob.
Do not attempt to repair the key fob yourself.
If you have any questions about how to replace the battery in your Mercedes key fob, consult your Mercedes-Benz dealer.
If you are experiencing any problems with your Mercedes key fob, consult your Mercedes-Benz dealer.

Recommended Battery Types

Battery Type	Voltage	Capacity
CR2025	3V	160mAh
CR2032	3V	240mAh

How to Replace Mercedes Key Fob Battery

Replacing the battery in your Mercedes key fob is a relatively simple task that can be completed in a few minutes. Follow these steps to replace the battery:

Locate the small screw on the back of the key fob and remove it using a small screwdriver.
Gently pry open the key fob using a thin object, such as a flathead screwdriver or a butter knife.
Remove the old battery from the key fob and insert the new battery in the same orientation as the old battery.
Snap the key fob back together and replace the screw.
Test the key fob to make sure it is working properly.