I researched the problem and saw the Whirlpool bottom freezer had the "won't defrost" as a common issue. My fridge is 12 yrs. old and the only other issue I had with it was the clogged drain tube which was covered under the initial warranty. I also had to replace the ice maker. When the freezer stopped defrosting, I tried a forced defrost (not advertised in the owner's manual, but can be found on the internet). That worked very briefly. I decided to buy the control board from Appliance Parts Pros and I'm glad I did. The project took me longer because I had to defrost the freezer. I didn't want to potentially mess up the new control board by having a major defrost. I followed the video that APP has with the part. Unplug the fridge, remove the light cover, pull out the control board cover, detach wires, take old control board out of it's holder (you can always take a picture before you do this to see how it was seated originally), remove the new board from the box, carefully break it apart as instructed in the video, you have to man handle it a bit, insert the new board in the housing, reattach the wires in the fridge, push the control board housing back into place (the guy in the video makes it look easier than it is), put the light cover back on, plug fridge in and then enter your fridge code using the fridge/freezer up/down arrows as instructed by the video. Close the door and you are good to go. I'm happy to say that it has been 3 weeks and the board is working perfectly.