Bad Control Board? Or Defrost Thermostat? Or nothing?

Refrigerator & Freezer Repair
,
1

Hi. Great website. Trying to figure out which component to replace – or if I need to replace anything at all. Here’s the story:

I had the classic cold freezer, warm fridge problem with ice buildup in the back of the freezer. I defrosted by unplugging and letting everything melt. A couple weeks later the problem returned. So, following a tip on this website, I ran the Forced Defrost Mode from the control panel. Since then everything has been working fine – defrosting occurs regularly. It’s been a few days. I have yet to reinstall the back panel and the ice maker in the freezer. Other than that everything is normal.

However, I recently ran the Defrost Thermostat and Defrost Circuit Test. It showed the 1 – S code indicating "Defrost Thermostat Shorted (Closed)." All other tests, such as for the thermistors, came back ok.

So, what’s going on? Did the Forced Defrost process fix something? Is my thermostat coming and going? Is my board coming and going? Thanks!

3

Thanks denman!. I have three questions: 1. Can you explain why everything seems to be working fine now? 2. Do you think re-installing the back panel will cause the problem to return? 3. Why is everything working normally (no ice build up and fridge and freezer both cold) if the defrost thermostat "never opens"? I guess I don’t understand what its job is when the Control Board initiates defrosting at set intervals.

Thanks again!

4

  1. Can you explain why everything seems to be working fine now?
    It sounds like you had/have a defrost problem, once defrosted the unit will operate normally until the frost/ice builds up enough to stop the evaporator fan from pulling air through the coils.

  2. Do you think re-installing the back panel will cause the problem to return?
    The odds are high that it will re-occur but who knows maybe it has fixed itself, this would be close to a miracle. I do not think having the back panel on will cause the problem or has anything to do with it unless you have a bad connection somewhere and it is opening that connection when installed.

  3. Why is everything working normally (no ice build up and fridge and freezer both cold) if the defrost thermostat "never opens"? I guess I don’t understand what its job is when the Control Board initiates defrosting at set intervals.
    The board starts a defrost cycle. It’s intervals are based on the number of door openings but the duration of the cycle does not change re: if it is 25 minutes it will always be 25 minutes. Now lets say all the ice/frost has melted off the evaporator coils in 15 minutes, you do not want all that extra heat in the freezer compartment so the defrost thermostat opens. This shuts off the heater till the cooling cycle restarts in 10 minutes.