Diagnosis
The defrost drain tube is clogged with food debris or frozen shut. This tube drains defrost water from the freezer to a pan below the fridge.
How to Fix It
1. Remove all items from the freezer and the bottom shelf.
2. Locate the drain hole in the back wall or floor of the freezer compartment.
3. Clear visible debris from the hole.
4. Pour a mixture of warm water and a small amount of baking soda down the drain tube to melt any ice plug.
5. Use a turkey baster or flexible drain brush to gently push through the clog.
6. Pour a cup of water down the tube to confirm it drains freely to the drip pan.
If That Didn't Work
The drain tube may be kinked or disconnected where it routes from the freezer liner to the drain pan. This requires pulling the refrigerator out and removing the rear access panel to inspect the tube's full path.
Heads Up
Do not use a metal hanger or sharp object to clear the drain. You can puncture the plastic liner. Use a soft plastic tube or a specialty appliance drain cleaning wand.