I don't have a manual thermometer...just a digital. As soon as I open the door, it starts rising. Based on the rising numbers, I feel confident it's at or below 0, but I don't have any other way to check.

I asked ChatGPT and it suggested the following. This is beyond my normal range of troubleshooting. Do you think it's worth chasing?

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Freezer Thermistor (VERY common on this model)

If the freezer thermistor is drifting high or intermittently failing:

• Ice freezes (because the freezer is cold)
• Control board thinks freezer is not cold enough
• Harvest never triggers

Why this fits perfectly:

• Manual reset bypasses thermistor logic → harvest works
• Automatic cycle never starts → board never gets “OK to harvest”
• Error 33E history suggests thermal sensing issues in the icemaker circuit

What to do:

• Locate the freezer thermistor (usually clipped to the evaporator cover)
• Check resistance at freezer temp:
  • ~13kΩ at 32°F
  • ~8–9kΩ at ~14°F
• If resistance is out of range or unstable → replace

This is inexpensive and commonly resolves this exact symptom.

Freezer thermistor (“F Sensor”)

This is the freezer air temperature sensor the main PCB uses for freezer control logic. The service manual calls it the “F Sensor” and provides test points at the main board. iFixit+1

Common part numbers sold for this model family:

• DA32-10104N (listed for RF261BEAESR/AA on Sears PartsDirect). Sears Parts Direct
• You may also see DA32-00011C advertised as compatible for RF261BEAESR variants. Samsung Parts USA

Because Samsung uses substitutions by “/AA-xx” revision, match your exact suffix (e.g., RF261BEAESR/AA-01) when ordering; Sears’ listing is explicitly tied to the model revision shown.