All refrigeration and cooling systems work on the same basic principle, using refrigerant to dissipate heat through a condenser coil. When a sealed refrigerant system is used, the same material can flow through the system, collecting heat from the beer, in this case, and dissipating the heat into the air. The compressor motor pumps the refrigerant through the system and the condenser fan blows air over the condenser fins (long, thin tubes through which the refrigerant flows while being cooled) to cool the refrigerant, which then flows back around through the evaporator, where it collects heat once again. (See Reference 1)
Clean the condenser fins and fan. Remove the back of the cooler by loosening the nuts or screws holding it in place. Look for the air intake for the condenser fan, since the fan will blow air over the condenser fins. (See Reference 2)
Wipe off the condenser fan to remove any accumulated dirt that might prevent it from spinning freely. Brush off the condenser coils. Be careful and gentle so that you don't bend the fins, as this will restrict the flow of refrigerant. If you bend a fin, slowly and gently bend it back into place with the pliers. (See Reference 2)
Blow out the dust and dirt between the fins with canned air or an air compressor. The cleaner the fins, the more efficiently your condenser will function.
Test the condenser fan by plugging in the beer cooler, opening the door, and turning down the thermostat until the fan turns on. Make sure the fan is blowing well before reassembling the back of the cooler. (See Reference 3)
Replace the condenser fan if it is not functional. Unplug the cooler and wait a minimum of five minutes for the electrical systems to fully discharge. Remove the mounting screws or nuts holding the fan in place. Gently pull out the fan far enough that you can see the wiring. Note the way the old fan is connected to the electrical wiring.
Remove the wire nuts or cut the wires. Match the wires from the new motor to their location. Usually the white wire goes to the chrome terminal and the black wire goes to the brass terminal, but consult the documentation that came with your cooler and replacement fan before proceeding. Connect the wires with wire nuts or electrical tape. (See Reference 3)
Mount the new fan into place and tighten the screws or nuts. Re-assemble the housing over the condenser coils. Plug in the beer cooler. Test the fan to ensure that everything is working properly. Enjoy cold beer.
Do not attempt to open or tamper with the sealed refrigeration system. Refrigerant is a legally controlled substance which you need a license to work with. If there is an apparent leak, you must call a professional. (See Reference 4)