Norcold N 180.3 3-Way Fridge 2017 Burner

@banjer54;
First off, does the Fridge cool on 120VAC ? . . . will take a couple of hours to cool.
Next, is your Burner Flame shape and color as defined in the Fridge Owners Manual?

If the Fridge cools on 120VAC and the Flame looks 'normal' . . . . before you rip apart the Burner Assembly suggest you inspect/check the Burner Exhaust Extension tube position.  The extension tube can slip during road travel and direct exhaust gas (heat) on to the cooling heat exchanger.

This forum thread {link} has a detailed discussion of the issue.
Burner Exhaust Extension

If you still need to rip apart the the burner box . . . there are parts lists, exploded diagrams on-line:

@banjer54 ;  So Fridge works fine on 120VAC and your 'flame indicator' is reporting the flame is active.

Perhaps you are not waiting long enough; various RV Manufacturers state their Propane Fueled Fridge units take between 4 and 24 hours to reach temperature.  My experience is that from dead-off propane always takes longer then 120VAC to cool down the Fridge.