I noticed the issue first when the water line running to my front door panel froze up (it is freezing inside the door panel in front of the freezer). Tried the youtube fixes foir opening the door and running warm water up the hose... and it would clear for about 6 hrs then freeze again. I noticed that my freezer was "extra cold" so I tried to lower the freezer temp on the digital LED thermostat (mounted in fridge side) but it didn't make a difference.

Next google steps led me to here to the Defrost thermostat. It was affordable so I ordered and installed. Took me about 20 minutes. I noticed medium frost build up on the coils, no loose ice anywhere back there blocking the fan or the path to the vent to the fridge.

Once installed I powered back up and gave it 30 minutes. I came back and found that the HI warning was on the digital LED thermostat warning me that the freezer temp was too high. I assumed that is because it lost a lot of cooling during the repair, because when I opened the freezer it was starting to get cold again. Checked my water line and it was working... yay!

Slept on it and checked again the next morning to find the freezer super cold again and the water line frozen. To be clear, the ice maker works fine since the water line for that is separate and located on the back of the fridge. The drinking water line runs up through the front door and that is where it keeps freezing because the Freezer side is super cold. I dont think there are any water line issues, I think it is just a symptom of the super cold freezer.

Chatted with a pro here at APP and they guessed the evap motor was out. I didn't own a multimeter so I just ordered the motor part. Before I opened the box I pulled the panel off and discovered the motor is running fine. So I returned it for RMA. Chatted with a pro again and she advised I test the heater coil for continuity.

So I bought a multimeter and followed the directions to test continuity on the heater coil. It has continuity... so now I'm not sure what the next step is. I have ruled out the following parts.

-defrost thermostat
-evap motor
-heater coil

Could anything else be causing the Freezer to run super cold and (presumably) not defrost. As I mentioned before, lowering the temp on the digital LED thermostat does not affect the freezer temp at all. That might be a clue.

Interesting. I'm having a similar issue with the frigidaire ffhs2611pf upright. It gets ice buildup along the back between the ice maker and the heater, but there's no ice on the heater coils. I can tell when the buildup starts because the evaporator fan gets loud, then I know I need to manually defrost it. Maybe I'll try this, but I want to make sure there isn't water leaking from the line to the ice maker first.