Introduction
An abridged version of my complete teardown of the Model 3 key fob. Check out the teardown for more details and examples of making a custom case should your housing also break.
You can check out how I built a replacement housing for the PCB here:
Model files and instructions are here: https://www.printables.com/model/624527-...
Tools
Parts
- 
                  
                  - 
            Prepare a surface to work on (ensure it's won't damage the piano black exterior coating) 
- 
            Gather your key fob and a small plastic spudger 
 
- 
            
- 
                  
                  - 
            Using a small pry tool, gently press into the small indent near the front of the key fob while pressing up to pop off the battery cover. 
- 
            Remove the coin-cell battery type CR2032 by prying upwards in the small recess 
- 
            Insert a fresh CR2032 coin cell battery being sure to match the correct polarity of the original 
- 
            If all you want to do is replace the battery, stop here. Otherwise check out my other guide for a full teardown! 
 
- 
            
To reassemble your device, follow these instructions in reverse order.