Ice flap in door wouldn't close

Take the face (the part with the buttons on the outside) off, disconnect wired connectors (three), take the screws out of the part behind that (4), and then find the solenoid value (on the right). It's attached with three screws. Mine was rusted beyond belief. I knew this was the problem, ordered a new solenoid valve, put it back in place with three screws (use new screws that fit, not the old rusty ones if possible). When testing, make sure you give the flap a couple of seconds to close. There is a delay, and I initially wasn't patient enough so I had to disassemble and assemble an extra time because of this.

Simply put: If your solenoid value is rusted and the value won't operate smoothly, order the part and install it. This is as easy as any repair could be.