Unplug the unit from the wall.
Pull out the vegetable crisper at the bottom of the unit. Look for a drain hole there.
Remove all the food from the freezer if there isn't a drain hole in the fridge compartment. Remove the screws from the back wall and pull it out to locate the drain line.
Fill a turkey baster with a mixture of 50 percent warm water and 50 percent bleach.
Squirt the 50/50 mixture into the drain hole and allow the water to flow through.
Pour a small amount of water into the drain line to test it. Reassemble the fridge.