I have a LG bottom refrig LBC22520SW. Pick it up from owner who stated that freezer works, refrig doesn't. So far so good I say. Transported it, sat for 4 days, plugged it in. Started up, compressor runs, evap fan runs, condensor fan too. Yayyyy. All while keeping perfect temperature (38 and 10), at settings 4 and 4, for approx 2-3 days. More yayyy followed by a booooo.

Then refrig went to 55 degrees, freezer 0 degrees, with NO evap fan. The temp display is showing NO leds on at refrig side of temp display, and 6 and 7 lit on freezer side.
Checking back 12 hours-same, but....Somehow I managed to trigger the defrost circuit. I opened the door and held the door trigger a view times to see if I could make the evap fan work. (Evap fan no operation at all.) Compressor off, cond fan off, all quiet. That must have set the defroster to on, (or coincidence?) Hmmm.... A few minutes later; pop, expanding, creaking, and sizzle. Yep That defrost is working. I'm happy 'bout that. In my path of understanding about these machines I read about ways to trick a defrost system by opening/closing the door switch in a certain sequence that makes defrost turn on. Did I inadvertently do that?

Is there a particular sequence in these LG's to invoke defrost?

Approx 20-30 minutes later: Frig 60. Freezer 38. Compressor on. Evap fan off. Another hour later and we are at: Frig 58 Freezer 20 (and comin' down), comp run, evap fan still off, condenser fan on ( that fan has aways worked properly)

Since the evap fan WAS working for first few days, that leads me to believe that fan system itself is working and the problem is that I am just not getting a signal to the fan now. Orrrrrrrrr, that the fan is freezing up causing fan to "freeze" up. Could that even happen? I banged on the back panel of freezer and that didn't make fan to start.

Are there any sensors that could affect the evap fan? Would they work for a while and then quit?

There is a possibility that the main circuit board is faulty. But it works for the first 2-3 days, so I am inclined to rule that out.

And what does 6 and 7 lit mean? Previously, I had fixed another LG's defrost system with a 567 error code. But, the LG manual doesn't show what ONLY 6 and 7 lit would mean. Sooooooo?

I may un-plug it and let it sit for 36 hours and see if that resets the computer; plug it in, and make another observation of the temp display, temps, and evap fan operation at that time.

Any ideas to the evap fan being a non event now?