Air Diffuser question

My refrigerator compartment quit cooling and I am trying to troubleshoot it. I have performed the following tests and and am looking for confirmation I am replacing the correct parts. Thank you for your help.

  1. Condenser fan and compressor both running.
  2. Fan coils below refrigerator are clean and free of dust. ec.
  3. Checked for evaporator motor running in freezer, it is running
  4. Freezer is plenty cold.
  5. No frost build up on coils in back of freezer compartment, so I think defrosting is working.
  6. No air flow through diffuser. Diffuser/air damper is closed.
  7. Bottom return air vent from fridge to freezer is open.
  8. Removed 2 thermistors from wiring harness next to air diffuser. one from freezer compartment and one in fridge compartment.
  9. Checked resistance. From the tech support people at Appliance Parts. at 36 degrees should read 29500 ohms- the actual reading is 8200, reading at room temp should 11200 actual reading is 3600.
  10. If I shut down the whole fridge at the power button inside the fridge and then power it back on the air diffuser damper will open, but then close again.
  11. I am assuming this is due to the failed thermistors?
  12. The air diffuser damper assembly is OK, I assume since the damper can open and close. But is remaining closed due to bad thermistors.
  13. So if I replace both thermistors, will this correct the problem with the dmaper remaining closed?
  14. Or do I need to worry about an issue with the main control board?

I hope someone can help. I feel like I am close and can repair this myself but am looking for some knowledgeable guidance.