Change battery of your Mercedes key. The way is simple: All you need is the key and TWO button cells type This video explains how to replace your battery in a Mercedes Benz Key ➤ Here you get batteries
Mercedes Benz Key-Remote Battery Change (Video)
All you need are two button cells of type CR2025. Remove the valet key by sliding the button and pulling. Look in the notch where the valet key normally sits, you’ll see a little ridge about 1/8″ below the top of the key, just below the slide lock.