Soooo its 2019 and its beginning to look like every 2 years or so the defrost timer goes on the fritz. This time I unloaded freezer then thawed with dryer but fridge still wasn't cooling properly based on nifty thermometer I now keep in fridge to monitor the temp. Its Saturday so I gotta figure out what's going on before parts stores close. I can see through coil cover that coils are iced over. After I Watch a YouTube video on how deforest timer SHOULD work I get trusty screwdriver and commenced to turn and test. I hear when compressor turns if then eerie silence. Then a pop of sorts can be heard, which I read is the heater coil kicking in. Rather than unload freezer again to see if coils are thawing the Holy Spirit gives me the idea to watch for water dripping into reservoir. Lo and behold, I can actually SEE the heater coil is red hot and I can see the ice melting. Whew, that saved an hour of time arranging frozen food! So I make a tiny mark on the defrost timer so I can watch it as it slowly turns through the cycle. Fridge is now cooling. Trusty thermometer is showing drop in temperature so it appears the defrost timer wasn't kicking on to defrost coils every 10 or so hours and the ice buildup kept the freon from doing its job. I'll keep monitoring it for a few days and if it sticks again I'll replace the defrost timer. Hope this helps someone.