Norcold 1210 turning it off for two days fixed it, why?

[EricPatTravels]

I have a Norcold 1210 refrigerator (new cooling unit April 2021). Old cooling unit died (ammonia smell) after ten years of full time use. Issue started a few weeks ago when the freezer could not freeze a tray of water for ice cubes. The freezer did have a build up of frost. While troubleshooting fridge it acts the same on LP & electric replaced thermistor and thermostat located on the fins at the top outside. At times the refrigerator fin temp (option 3 main display) would reach the low 30's then a few hours later it's back up to 44 degrees. After a few days I gave up and shut it down, two days later I turned the refrigerator back on LP and the fin temp went from 49 to 34 in a few hours, left it overnight in the AM temp was 19 degrees. Refrigerator has been running for two days the fin temp is staying between 19 and 24. I did hear the outside cooling fans running from time to time.

[dougrainer]

When you replace the Norcold 1200 series COOLING UNIT, you ALWAYS replace the 2 fans and the Fan Tstat. What you describe is intermittant cooling fan operation. When I replace 1200 series Refer cooling units, besides the fans and fan tstat, I run 2 wires from the fan tstat down the back side to bypass the fan tstat to run the fans 24/7 to aid in diagnosis. What you can do is install a small 120 volt fan blowing up from the rear bottom outside access door and retest the refer. If it operates correctly you will need to pull the refer and replace the fans and fan tstat. Doug