How to Replace the Battery in an Older Mercedes-Benz E400 Key?

[OLincoln]

Here are the detailed steps to replace the battery in a Mercedes-Benz E400 key: 1. Locate the switch on the back of the key fob and pull the top part outward to remove the internal metal mechanical key, revealing a small notch. 2. Use a flathead screwdriver or similar tool to pry open the key fob cover along the notch. Once a gap appears, you can manually separate the cover. 3. After opening the key fob cover, remove the old battery and replace it with a new one, paying attention to the correct polarity. 4. Reattach the key fob cover and reinsert the mechanical key to complete the process.