Not sure of the age...just purchased the home. The fridge started heating up and after some learning, then debugging I discovered that the coils in the freezer were not defrosting. I have been debugging this, but am not sure where the problem lies. The defrost heater measures out at 33 ohms, which is within spec, and the defrost thermostat measures out at 0 ohms when hit with circuit cooler, and somewhere in the 28k range when warmed. I put it back in and tried a forced defrost, which didn't seem to work. While it was in the forced mode, I pulled the connectors, and measured the voltage at 28v or so. Obviously this should be 120v, so what might be causing this low voltage?

How do I get to the board? I can't figure out how to get the cover removed, and I'm afraid I'll break something if I pull too hard on the housing.

That video gave me what I needed to get to the main board. After further testing the defrost seems to work just fine when forced and during the system tests. I decided to put it all back together and see what happens. Perhaps the main board isn't doing automatic defrosting correctly? I'll post what happens in the next day or two.