Where is the freezer drain plug on a Frigidaire model FRS26ZRGB4 Won't freeze, water frozen on bottom of fridge.

You need to clean it. Unplug and remove the cover to the freezer coils. At the bottom of the coils there is a drain pan which gets stopped up with food and other things like dirt, meat juice, etc. Wash it out well with Windex and a water hose nozzle to unstop it. Be careful not to bend any coils or Freon (refrigerant) lines. Then remove the back and spray down coils and fan blades with soap and wash them off with water hose nozzle. You may also find coils at the bottom of the drip pan which are part of the hot gas line coming out of the compressor which helps to cool the refrigerator and reduce energy use and evaporate the water. The problem is that the coils get caked with dirt and no heat transfer can occur then. Clean that well, maybe even with vinegar, until it's clean. Then spray down the coils with a hose nozzle. It does not take much water, but it's the only way to clean coils and get grease and dirt off them so that they transfer heat well again. Just vacuuming off does not work nearly as well and you have to clean the fan because just a 1/16" of dirt on edges of blades kills 30% of airflow. Pull out drain pan and clean with bleach and soap if it comes out, or clean it and vacuum out with wet-vac. It's very important to keep the coils clean or the dirt will cause the compressor to burn up.