What to Do When a Mercedes Key Fob Battery Dies?
2 Answers
Mercedes vehicles come standard with keyless entry and keyless start functions. If the battery dies when you're trying to open the door, the owner can pull out the hidden mechanical key inside the remote to unlock the door and enter the vehicle. Similarly, you can remove the push-button start cover and insert the key to start the engine. Here are the signs that a Mercedes key fob battery is running low: 1. The remote control range becomes shorter. For example, you might normally unlock the car from 5-6 meters away, but now you have to stand right next to the door. 2. The key occasionally malfunctions. For instance, where a single press used to open the door, now it takes two or three presses. 3. The indicator light on the key becomes dim or flickers. Some higher-end models will display a warning on the dashboard to alert the owner that the key battery is running low.
Last time my Mercedes key suddenly stopped working, the screen wouldn't even light up, which really stressed me out. But I quickly found the solution: first use the mechanical key blade hidden on the back of the key to open the door, then place the dead key against the start button - this spot is usually inside the center console, in that small indentation with the key symbol. After pressing the start button, the car actually responded! Later I found a nearby convenience store and bought a CR2025 battery. You can open the key by pushing the back cover sideways to replace the battery. Make sure to get the same model, and install the battery with the smooth side facing up. After replacement, test the remote locking function. Now I proactively change the battery every six months and always keep two spares in the trunk - haven't been bothered by this issue since.
