Gene, how much ice is acceptable on the evaporator core? The ice has always been confined to behind the panel and the opening (cold air passage) from the freezer to the fridge is always open (not iced shut), there is a fan that blows cold air to the fridge, it didnt run, but after thawing out, it started to run.

I already checked out the upper blend door. Its working fine. If for some reason, the small fan never runs allowing the fridge to warm up, that would overcool the freezer and undercool the fridge, which is what is happening.
What amount of ice on the evap core is normal? The ice is on the evap fins only, fairly thick, but never visible in the ice box, limited to just behind the panel. There is no ice above the evap core, the small fan is free to turn, the inlet grille (the one that snaps in the back panel) is clear and free of any obstruction.

I'm thinking the small fan just isnt running. Its a durable looking "brushless" design, spins free and smooth and did start to run after I was almost done defrosting. I didnt unplug the fridge, I just turned the digital freezer control down to minimum and it went to a "-" for the freezer and also a "-" for the fridge. After I thaw it, the fan runs, all is well. It went about 5 weeks since I did this last. I'm certain something is intermittent. But working fine now, going to be tough to locate.

With this extra info, if this helps, let me know.

What is the purpose of the evap core heater element? When is it supposed to come on? Is it an automatic feature or do I somehow have to put this into a "defrost" mode to make it work and is it used to keep the evaporator clear of excessive ice???

Gene, after reading your reply, I'm convinced its not running the heater unit every 8 hours like you said. The return air flow in the freezer part becomes blocked. I going to assume the heater unit is not running. My evap coils become heavily iced over, till the return air vents in the freezer (after looking at the air flow diagram you posted) are plugged.

I cant afford down time (its working now as I have used a heat gun to remove the ice for a second time in about 6 weeks) and I just ordered your heater element and thermostat and will just replace both. Where is the thermostat located? And if that doenst fix it, the control board. Where is that unit located too, I assume under the control settings panel.

Thanks so much Gene.

Our fridge is 6 years old. It has been freezing the lower compartment on and off for a couple years. Last week I noticed the fridge side was not as cold as usual, and continued to get worse. I would hold my hand up to the diffuser and could not feel any cold air entering. After reading different forums, I figured the diffuser needed to be replaced but was not entirely confident with my decision, so I called a repair guy to come look at it. He said that condenser coils looked good (not too much dust) and both fans were running. When he took off the back panel in the freezer, he said the problem was the condenser since only the bottom few coils has frost on them and the rest were just wet. His solution was to buy a new refrigerator. He didn't even look at the diffuser or run diagnositics on anything else. As a last ditch effort, I turned the fridge off for a couple hours, cleaned everything, took out the diffuser and could see the vents were closed and somthing was rattling around. So I opened the vents manually, replacing everything and turned on the fridge. 24 hours later the fridge is cold and the evaporator coils are frosted all the way up. I also performed the digital diagnostic test I found online and all checked out except the diffuser which did not open and shut on its own. I plan on replace the diffuser myself. My question is could I really have a problem with my condenser?

Hi,
Yeah, he looked at the evaporator coils and said I probably needed a new COMPRESSOR (sorry I said condenser before).
Jill

Hi Jill,

The evaporator unevenly covered with frost could happen because of dirty condenser (on the back of the refrigerator) or the refrigerator can be on defrost cycle at that time or the defrost cycle just finished.

I would recommend to keep the diffuser open with a toothpick and watch the temperatures for a few days. Normal temperatures should be: about 0°F in the freezer and 36°F-39°F in the refrigerator. If it will work good, replace the diffuser.

- The diffuser Part number: 2216112