I think we just covered this here, or maybe it was on the TM Fans group over on Facebook…
Anyway, here’s the simple way to diagnose. Sounds like you can light the pilot manually, yes? If so, WITH THE PROPANE TANKS CLOSED, one person goes outside, removed the panels, and looks at the back of the fridge. The other person is inside and just clicks the red “Light” button. Does the person outside see a nice fat blue spark? If not, it’s either the piezo igniter or the spark cable. Both are easy to change but might involve pulling the fridge forward a bit. Here’s a parts list (I also included the burner and thermocouple, just in case)
Norcold 619153 Spark Electrode
https://a.co/d/4m7Vx1m
Norcold 61645622 Piezo Ignitor
https://a.co/d/1umCr5T
Norcold 621953 Burner/Orifice Kit
https://a.co/d/b2MRkWx
Norcold 619154 Thermocouple
https://a.co/d/ieoefro