LG EBR88309723 Main Control Board LRFVC2406s

[Boo Consulting]

Does anyone know where to get a board level schematic for the main control board?  Or a process sequence diagram chart?

 I have an EBR88309723 that generates a defrost sensor error d5 F ~ every 8 hours.  The defrost thermistor sensor is working (10K - >80K hot to cold), a wider range than other model defrost sensors. The freezer section thermistor is a more narrow range ~ 4K to 35K more common to other fridge models.     

Otherwise the fridge is working great until the coil builds up frost after 3-4 weeks.  The defrost heater or cycle is not coming on. All sensors and heaters test fine. Compressor is working well. Maybe the defrost sensor is wrong.

The test mode button does not work. It worked some weeks ago when I had a different fault code ECL, there is no leak of the low pressure side.

I have ordered a new replacement control board however I am more interested to troubleshoot the problem root cause. 

The defrost thermistor ACM75678705 has a larger range than other refrigerators, however it is changing with temperature. Is this is normal for new LG refrigerators?

Thanks,

Rick

[dfphoto]

sounds like your sensor is in need of replacing...

[Guest]

With what I just read about thermisters it seems yours could be faulty if you're getting a resistance reading close to 80k, but it's not clear from the article that a higher resistance in this situation is really an issue. I'd have to research a little more to be more confident. 

For the temperature range of a refrigerator and freezer the resistance should top out around 10k. 

I didn't look up what other sensors are in play but I'm inclined to think you should look at those other potential sensors before worrying about the Thermister.