First, turn the referigerator off at the circuit breaker or unplug it. Take everything out of the refrigerator. Then remove all shelfs, including the bottom crisper drawers. In the center back of the refrigerator you will see a panel. This is the panel where "Twin Cooling" vent circle at the top is attached.
Notice that there are three Phillips screws at the bottom. Two on the panel and one on the center bracket where the shelf bracket would go into. Remove these three screws. On that same center bracket, follow it up all the way to the top of the panel. Notice a small cover at the top of the center bracket just above the last spot a shelf bracket could be inserted. Use a flat head screw driver and pry out that small cover. You will see another Phillips head screw behind that cover, remove it. At the bottow start pulling the panel away. Now, on the right and left sides of the panel you will notice little arrows. These point to the spot where you need to pull in the panel towards the center to release the plastic tabs that help to hold the panel in place. Do the bottoms ones first which will further release the panel. Then do the next set of arrows above it. The panel will side down and come off. Note: Sometimes the panel is stuck at the top due to ice build up. You can either continue to wiggle it in an attempt to remove it from the ice. Or let the ice melt (This may take hours depending on the ice build up).
In the above picture you will notice the ice build up that this refrigerator had. This ice went up to the fan and that is what was causing the noise from the fan. I took a hair dryer and melted the ice on the evaporator and the fan. Notice how the rest of evaporator does not have ice. There is a heater element that runs around the outside of the evaporator but not around the top. I think that was a design flaw. I have owned the refrigerator for little over a year. So, it took that long to build up. I guess I will need to do this about ounce a year.
Reverse the process to put everything back. Don't forget to attached the two wire harness back into their plug. Slide the panel back in place, it should easily snap in place. If it is hard make sure the wires are not sticking out at the top which would prevent it from going into place. Put all Phillips screws back, shelfs back and turn the power on.