Unplug the freezer from the electrical socket.
Remove the screws securing the kick plate to the bottom of the freezer with a Phillips-head screwdriver. Remove the kick plate.
Open the freezer's door. Reach through the opening at the bottom of the freezer and grasp the switch from the back side.
Squeeze the switch's locking tabs and push the switch out. Disconnect the switch's electrical connectors.
Plug the electrical connectors onto the leads of the new switch.
Push the new switch firmly into its slot until you hear the locking tabs click into position.
Close the door and replace the kick plate. Plug in the freezer.
Push the switch by hand while the door is still open. The light should go off. When you let go of the switch, the light should turn on.