Remove the power from the refrigerator before opening the dispenser.
The control panel at the top of the dispenser will pry off the dispenser with a putty knife or a small flat blade screwdriver. Pry out in small increments and move over 2 inches and pry again. You might need to go around the control panel 2 times to get it off. If you pry too much at a time the panel will break.
With the control panel removed remove the screws that hold the bracket that supports the switches and the flapper door.
Pull the bracket out far enough to access the spring and the flapper door.