If your refrigerator or freezer just isn't cooling as effectively as it used to, there are a number of things that can be causing the problem. One potential issue is that the evaporator fan may be bad. Of course, before you get into testing the fan, make sure your refrigerator's thermostat settings are properly set and that nothing is obstructing the flow of cold air in your freezer. If everything checks out OK-then here is how to test your refrigerator's evaporator fan to see if it is working like it is supposed to.
Before working on your refrigerator, always make sure you either unplug the unit or turn off the circuit breaker that powers it.
Remove all of the food items from your freezer and place them into a cooler to keep them from melting. The refrigerator's evaporator fan is located at the rear of the freezer compartment, so if you have an ice maker, you will have to turn off the water supply to it and remove the ice making machine.
With the freezer now empty, remove the panel that covers the evaporator fan. This is usually either held in place by screws or retainer clips. If yours features retainer clips, use the screwdriver to press the clips in to allow the panel to pop off. Just be careful you don't break the clips.
Remove the two screws that secure the fan housing in place. If you still don't have access to these screws, then you may have to remove the entire rear panel of the freezer.
When the evaporator fan is released, notice that there are two wires (or three depending on the make) attached to it. Draw yourself a schematic so you know exactly where these wires get connected once you are finished testing the fan.
The wires are connected to the fan by slip-on connectors. Use the needle-nose pliers to pull the connectors off of the terminals. Pull them off by gripping the connector, NOT the wire. Inspect both the wire connectors and the fan's terminals for any signs of corrosion. Spin the fan's blade to make sure it spins freely and is not seized up.
With your evaporator fan now free, close the freezer door and find a flat, clean work surface to set the fan on. Set your multitester to read ohms, which is normally either the X1 setting or the RX1 setting, depending on the brand of tester.
Touch one probe to one of the fan's terminals and the other probe to the other terminal. The multitester should read "zero" ohms. If the tester reads anything other than "zero," then the fan should be replaced. If the tester does read "zero" and the fan blade spins freely, then reinstall the evaporator fan; it is still operating correctly.