My wine chiller doesn't have a compressor, it uses a heat sink fan and a "cold sink" fan. I believe it uses a peltier between the two. The internal temperature according to the display is 80 degrees, which I believe to be accurate, but that means something is broken because it should be chilling to 65 degrees. Room temperature is near 70 degrees, so something is heating up the inside of the wine cellar.
Both fans are running, and the peltier makes a barely audible humming sound when it's plugged into the circuit board. Since the peltier hums, and the inside is hotter than room temperature, I thought maybe something happened and the polarity got reversed somewhere in the circuit. I reversed the power cables to reverse the polarity, as a method to check if the polarity was already switched somehow by a short out in the circuit board. This caused the internal temperature to climb really fast, bringing hot air from the outside in instead of from the inside out as I was hoping. To me that suggests that polarity is not the issue, and the peltier is working to some degree.
To summarize, the posted temperature seems accurate, the two heat sink fans are operating, and the peltier has the correct polarity and works to some unknown degree. However, the internal compartment is about 10 degrees warmer than room temperature. Ice packs in the compartment will cool it quickly, but upon removing, the compartment rapidly heats up again. Something is warming the internal compartment. Could this somehow be related to a faulted NTC thermister?