This morning I noticed our fridge wasn't as cold as it should've been. Verified with my IR thermometer. Went online and found a site that helped troubleshoot problems, repairclinic.com. Found a description of my issue and some probable causes. Also looked it up on the Amana website and found the parts digram/list.
Using this information I was able to disassemble the lower parts enough to expose the frosted-over evaporator. I used my heat gun on low to defrost it, and reassembled. Verified the upper damper door was opening. Now operating normally!
What I think happened was the bottom freezer was left ajar recently, and with our humid weather in the PNW lately (always?) the freezer frosted pretty badly. We didn't think anything of it, assuming it wouldn't affect the operation. But, the evaporator was frosted over solid, so no air flow over it despite the compressor and fans running. This resulted in the freezer going to below zero, and the fridge going to near 70ºF. Lost a few things from spoilage, but glad to save the usual service call fees.
The evaporator fins are visible through the slots in the bottom of the rear wall of the freezer drawer, so now I know where to check if this happens again.
