The drain pipe is located behind the back cover in the Kenmore top mount refrigerator. Disconnect power to the refrigerator, and pull the appliance away from the door. You may need help with this step. Remove the back cover on the upper portion of the refrigerator rear, removing the screws that hold the cover in place and lifting the cover up and off. Locate the freezer floor cover, and remove the two screws holding the cover in place in the front of the freezer. Slide out the freezer floor (after removing any food sitting on the floor).
Once the back cover is removed, find the condenser coils. The drain pipe is located under the coils, and the pipe is accessible after removing the ice, either with warm packs, a hairdryer set on low, or hot, damp cloths. Check the drain pipe for a frost blockage, which can be cleared with a warm, damp cloth, and remove any other debris that might be obstructing the drain.
Pour hot water down the drain using a turkey baster repeatedly until the water moves easily down the drain. Once the water is moving easily, combine hot water and baking soda and squirt the mixture down the drain several times. Restore the ice and the back panel to the refrigerator.
If the defrost drain becomes clogged on a regular basis, disconnect power to the refrigerator and remove the toe grille on the front of the refrigerator. Clean the coils with a vacuum cleaner with a brush attachment, and move around to the back of the refrigerator and clean the condenser fan as well. These components help maintain proper air flow through the refrigerator, which can help prevent frost or other water problems that can obstruct the drain pipe.