I was getting the er 1f error and my freezer was building up ice. Removed back cover and inspected the fan. Defrosted and everything was fine. This happened a couple of times over the past 6 months. Fan working normally. One day when the unit was running fine, I noticed a build up of ice in the bottom on the freezer compartment. I shut the freezer and inspected around the gasket and noticed the seal was not tight. Shut door with a piece of paper and pulled around the seal. Decided to replace the all of the gaskets......So far so good.