1. Locate the key fob. It is usually a small, rectangular device that you use to unlock and start your car.
2. Press the button on the side of the key fob to release the key.
3. Slide the key out of the fob.
4. Flip the key over so that the back is facing you.
5. Locate the small, round battery cover on the back of the key.
6. Pry open the battery cover using a small screwdriver or your fingernail.
7. Remove the old battery from the key.
8. Insert the new battery into the key, positive side up.
9. Replace the battery cover.
10. Slide the key back into the fob.
11. Test the key fob to make sure it works properly.
