I have a Fridgidaire freezer LFFU1466GWO that will run 24 hours a day and not turn off. It is reaching temp. I emptied it out and there was ice about 1/2" thick over the drain hole. Thawed for over 24 hours, cleaned up the water and when restarted, didn't turn off at temp again. If I turn the t-stat knob down, freezer still stays running until I turn off completely. Any ideas? I did remove the panel over the coil on the inside and everything was clean, no ice on coil or dirt on fan.

Suggest that you purchase some type of thermostat and place in freeze to see what the actual temperature is. Then try to diagnosis what the problem may be. May be defective thermostat or may be temperature is not getting cold enough. At this time you really don't know what the problem is.