How to Replace Your Mercedes Key Fob Battery Replacement
Having a dead battery in your Mercedes key fob can be a huge inconvenience. When that battery runs out, you can no longer unlock the doors or start your car remotely. Fortunately, replacing the battery yourself is a quick and straightforward process. This guide has everything you need to know to safely change the battery in your Mercedes key fob.
What You Need
Gather the following tools and supplies before getting started:
- New CR2032 or CR2025 3-volt lithium coin cell battery (recommended brands: Duracell, Energizer)
- Small Phillips head screwdriver
- Clean towel or mat to work over
- Bowl or plate (optional – for screws and old battery)
Use a clean, well-lit workspace like a table or desk when changing the battery. Lay down a towel or mat to protect the work surface as well as the key fob components once they are removed. Having a small bowl nearby gives you a safe place to set screws or the old battery rather than losing them.
Carefully Take Apart the Key Fob
The first step is to separate the two halves of the plastic key fob casing:
- Identify the seam on the key ring or Mercedes logo side of the fob.
- Take your screwdriver and gently insert it into the seam, working it through until there is enough space to twist the tool and pry apart the casing. Go slowly to avoid damaging the plastic.
- Once the two halves come free, remove the circuit board from inside and set it aside. Be careful not to lose or throw away any foam padding or the battery located on the board.
Troubleshooting Tips
- If unable to locate the seam, check all sides for small slits around the edges or Mercedes emblem.
- Overly forceful prying can crack the casing; apply steady, even pressure.
- If a piece of the casing does break, the key fob may still function properly when reassembled.
Remove the Old Battery
After separating the casing and removing the circuit board, changing the battery itself is fast:
- Note which side of the old battery is facing up so you can orient the new one correctly.
- Gently lift out the CR2032 or CR2025 battery to remove it. Avoid losing or displacing any foam padding stuck to the board.
- Check for any leakage or build up on the battery terminals. Clean with a cloth if needed.
Install New CR2032 Battery
The final steps to complete the key fob battery replacement are:
- Orient the new CR2032 battery with the positive (+) side facing up, matching the old battery. Ensure any foam padding stays aligned underneath.
- Briefly test operation by pressing buttons on the fob before reassembling. The lock/unlock and panic buttons should work.
- Carefully snap together the two case halves, realigning all edges. You may need to apply a bit of pressure for it to fully close.
Key Fob Replacement Tips
- If the key fob does not work after changing the battery, double check that the positive and negative terminals align correctly.
- You may need to reset or reprogram the key fob by holding down two buttons simultaneously near the vehicle. Consult your Mercedes owner’s manual for details.
- In rare cases, the key fob may need professional service if it will still not work properly after changing the battery and attempting resets.
Avoid Future Key Fob Battery Issues
To maximize your new battery’s lifespan and minimize premature drainage issues:
- Store key fobs away from extreme temperatures inside the home or car. Heat wears down batteries quicker.
- Limit proximity operation use to decrease battery strain. Manually lock/unlock instead sometimes.
- Consider keeping a spare CR2032 battery in your glove box in case it dies while on the road.
- Be alert for fading key fob range and respond promptly with fresh battery.
Here are signs it may be time for a replacement:
- Vehicle no longer responds to key fob button presses.
- Lock/unlock range seems significantly reduced.
- Key fob red LED indicator when buttons pressed seems dim or no longer illuminates.
In Summary
- Pry open key fob plastic casing careful with screwdriver
- Remove circuit board and old CR2032 battery
- Note orientation and insert new CR2032 battery
- Test fob operation, then snap casing back together securely
Replacing the battery yourself avoids paying for an automotive locksmith or dealership service. Just be sure to properly recycle the depleted battery. With a new power source, you’ll be reliably operating your Mercedes by remote once again!
Frequently Asked Questions
What type of battery does the Mercedes key fob use
Mercedes key fobs use a standard CR2032 3-volt lithium coin cell battery.
How often does the battery need replacement?
Typical Mercedes key fob battery lifespan is 1-3 years with average use before requiring a replacement.
Can I change the battery myself?
Yes! Following the steps above, you can safely replace the key fob battery on your own rather than paying for automotive service. Just take care when prying open the casing.
What if my key fob still doesn’t work after a battery change?
Double-check the positive/negative terminal orientation first. You may also need to reset or re-synchronize the key fob by holding two buttons down near your Mercedes. Consult your owner’s manual or contact the dealership for assistance.
What should I do with my old dead battery?
Properly dispose of the depleted battery by bringing it to a retail store that recycles batteries or a dedicated recycling facility to avoid environmental contamination. Do not simply place in the trash.