How To Open Mercedes Key Fob For Battery. This process for how to change your car key differs slightly for each key version. Pull until the key releases.
For the smart key, pull the latch at the end of the key holder, stick your key horizontally into the open slot, and lift the battery compartment out to replace the batteries. If the key fob requires multiple clicks to open the door, only works on occasion, or does not work at all, you may need to replace its battery. Multiple clicks needed to unlock the doors.
Tap the smart key against your palm until the battery falls out.
If you don’t see this light, the problem is that your key fob is defective. Pull the tab at the bottom, remove the cover by pushing the key into the narrow end of the slot then place the battery inside. Most newer models include a chrome key, which only needs one cr 2025 battery. To change a mercedes key battery, start by pulling the silver tab at the bottom of the key holder back to release the manual key.