In this case I would go directly to the defrost drain. It can be accessed by removing the evaporator cover on the back wall of the unit in the back lower half of the freezer compartment. Never use a wire or anything sharp that can puncture the rubber drain hose on the unit. I use a hair dryer and after I get the ice cleared, I chase the hose with a piece of weedeater line long enough to see the end under the unit at the defrost pan. Hope this information was helpful for you!