Locate the seam on the edge of the key fob where the two halves meet.
Insert the tip of a small flat-head screwdriver into the seam and gently twist to pry open the fob.
Work your way around the perimeter, carefully separating the two halves without forcing or damaging the plastic.
Once open, identify the battery sitting on the circuit board inside the fob.
Remove the old battery by gently lifting it out, noting the orientation of the positive and negative sides.
If needed, clean the contact points on the circuit board with a lint-free cloth to ensure good electrical contact.
Place the new CR2032 battery into the slot, making sure the positive side faces up (or as indicated).
Align the two halves of the key fob and press them together until they snap securely.
Double-check that the fob is fully closed and no parts are loose.
Test the key fob by pressing the buttons to verify it functions correctly.
If the fob does not work, re-open and check the battery orientation and contact points.
Dispose of the old battery properly according to local regulations.