On-line reading led me to believe it was a clogged condenser drain line on the freezer side. After verifying the freezer drain line was not clogged, I discovered that the condenser drip tray on the refrigerator side was rusted through. Once I had the replacement part, it took about 30 minutes to install. Issue is resolved. On a side note, it appears the replacement part has a thicker galvanized coat that the original. So hopefully won't see this issue again.