MB Medic Mercedes-Benz Repair Guides, Service, How To DIY
How to change the battery on the Mercedes Benz Smart Key Fob. How do you know you need a new battery? The remote lock or unlock range is poor. Or even worse, the door lock/unlock is not even working. These videos will show how to change the battery on different Mercedes-Benz Key Fob Remotes. There are several Mercedes Smart Key remotes, so look at the correct video.
We strongly recommend using a Lithium battery like these ones, as they last much longer.
First, you need to identify which key you have. There are several models. The current Smart key fob is the chrome key with a triangle panic button.
If your buttons are worn out, consider adding a silicone case to avoid further damage to your key. You can get a cover case for less than $10, see here.
How to replace/change Mercedes Key Fob Batteries
Step-by-Step Videos
1. Current Chrome Key
Triangle Panic Button
Triangle Panic ButtonIt requires ONE CR 2025 battery.
2. Chrome Key
Round panic button
Round panic buttonRequires TWO CR 2025 batteries.
Make sure to get Lithium battery like these ones on Amazon.
3. Older Smart Key Fob 
Black Plastic Housing
Requires TWO CR 2025 batteries
4. First Model Smart Key Fob Remote
Oldest Smart Key Black Plastic Housing
Requires two TWO CR 2025 batteries
Here is one long video showing how to replace the batteries in any of the Smart Key Fobs made by Mercedes Benz.
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How to remove the plastic cover over the battery. It is made extremely stupid!
My old mercedes version key fob, will not lock the car, only unlock it. I press the lock button and it does not work. I changed the batteries like on your video, thanks you, any advice?
My old mercedes version key fob, will not lock the car, only unlock it. I press the lock button and it does not work. I changed the batteries like on your video, thanks you
Very useful visual display. I managed to get one of the battery contacts twisted when I changed batteries last time, your video enabled me to straighten out the contact and use the fob again.
My wife changed her key fob battery today and now the driver side headlights and tail lights wont turn off. Related to batrery replacement? (GLA 250)
I have a 1998 Mercedes SL 500. I have a KR 55 switchblade type of remote opener.
My Mercedes dealer could not get it programmed. Also I would like to take the key from my old one and put it the replacement.
2005 Vito van. What battery type do I require .? Many thanks
Key fob battery, silly me 😁
I was mugged and my car keys for mercedes e-class kompresor car however i have a spre key which is working i wonder the other they stole can be deleted so they cant use it
Yes it can be deleted with the proper scanner.
i replaces battery for remote key for Mercedes e 320 work only for a week replace battery again not work at all !!! what is next step please
Sounds like you have a defective key. Do you have a spare key to test? Also does the key start the car? Each key has to functions (circuits) one to unlock the car and the second to start it. For the most part they are independent of each other. That’s why a dead key should still be able to start the car.
I changed my batteries in my key fob (the one with the round panic button) and at first it worked immediately, but now it works periodically and my car alarm randomly goes off even if I haven’t been in the car for several hours! What’s wrong??
The problem is not your keyfob. Your car battery may slowly drain causing the alarm to go off.