The drain is located under the evaporator coil in the freezer.
In order to get access to the drain you have to remove the freezer floor (#25 on the
liner break down diagram) and the evaporator cover (#16 on the
liner break down diagram).
To defrost the drain and clean it you can use a hair dryer and hot water.
- Here are the break down diagrams for the Whirlpool refrigerator
Model ET1NHMXKT00
Good luck.
Gene.