GX5SHTXVA00 Freezer coils/condenser still freezing-over causing warm fridge.Thermostat changed

[fridge123fr]

Whirlpool GX5SHTXVA00 s/n KW1504332

About 6 years ago it started freezing-up the condenser/radiator/coils in the freezer section which also regulate the fridge section and caused the fridge to become too warm. I used a heat gun on the back wall of the freezer to melt the frozen condenser behind it, and then a turkey baster to suck the water out of the collection pan at the back bottom. Had to do that about once or twice a year.

I replaced the thermostat a couple months ago and siliconed over the wire nuts and everything as per installation tutorials. A couple weeks ago it froze over again, so I defrosted it again and then it sort of happened again right after. So I set the freezer section to only 1 out of 7, and now it seems ok but might happen again it seems. Basically the freezer is still very cold on "1" because the coils I think are slightly frozen-over and keeping the coldness in the freezer. I have the fridge set to 4 of 7 and seems to be cold enough - I think we previously had the fridge at only 1 in order to help this problem but 4 seems to be doing ok for now

[EthanRanft]

If it keeps freezing up, you may have a bad connection at the thermostat, bad heating element (unlikely), or bad control board. The control board can fail in a couple different ways. Sometimes it is actually going into defrost like it should, but it never actually shuts off the compressor in the defrost cycle, which means it doesn’t fully defrost, and eventually, after several weeks usually, it will be frozen up again