This is a video tutorial where you can see how to replace or change the key fob battery on Mercedes-Benz A-Class, B-Class, C-Class, GLE, GLA, S-Class, etc. in just 4 simple steps.
1. Remove the key blade pushing down that black button
2. Remove the black panel using the key blade
3. Remove the old key battery (CR2025) and replace it with the new one
4. Put back the black panel and then the key blade into the key fob.
This procedure is also avalaible for Mercedes-Benz E-Class, SLK, C63S (2018), C-Class (2015-2019), A-Class (2013 -2018), B-Class (2015-2019), GLC, S500 AMG, etc.