To change the battery in a key fob, follow these general steps

Identify the type of battery needed

Open the key fob

Take out the old battery and dispose of it properly

Place the new battery in the correct position, taking care to follow the correct polarity

Press the buttons on the key fob to make sure it's working properly

Replace the cover and make sure it snaps securely into place

Be careful when opening the key fob and removing the battery