About 5 months ago I replaced all (3) thermisors and that seemed to fix the vague tempurature variations. This week the customer called back with more tempurature swings, mostly getting warm in fresh food and freezer section. This is what I did yesterday. Checked the mother board for physical damage on the back and any relays that may have looked bad, all good. Cleaned the condensor. The compressor and condensor fan seemed to be working. I opened up the evaporator area and replaced the defrost heater and limit, the evaporator was only icy near the top and it didn't take much to defrost it. The reason i replaced the heater is because the glass was broke on one end and it was all gray and cloudy inside the tube.
The customer called back 24 hours after my latest repair and still having temp issues. My suspision is that its a evaporator fan issue. Finally I will ask my question: Is there a 'cheat sheet' that someone might have that gives the various circuits and values to be looking for so I can stop guessing?
Also, if I determine that it needs a new evap fan, should I get a new board at the same time?
Also, the board on one of my websites says it would be P/N WR49X10152 but there is a sticker on the back of the fridge that says to replace the board with P/N WR55X10156, I should go with the one printed on the fridge? I believe this is a variable speed compressor unit.