How to Replace the Battery in a Mercedes-Benz E300 Key?

[Jacob]

First, find a screwdriver or a pry tool, then pull out the metal key. You will see a gap inside, use gentle force to pry it open. Remove the old battery and install the new one (with the positive side facing outward). Finally, after replacing the battery, reassemble the key.

[LeLandon]

Changing the battery for a Mercedes-Benz E300 key is something I've done myself before, and it's quite simple. There's a small button or sliding groove on the key; press it to separate the shell. Inside, you'll find a round coin battery, usually the CR2025 model, which costs just a few bucks for a new one. Be careful not to damage the surrounding parts when removing the old battery. When installing the new one, make sure the positive side is facing up, or the key might not respond. After reassembling, test if the buttons light up or try unlocking the car by approaching it. Don't worry about using too much force—the key is designed to be sturdy, but avoid dropping it hard. It's a good idea to keep a spare battery at home so you won't panic when the battery runs out.