Not a norcold here but a Dometic... Had an issue not unlike yours.
Wound up doing the disconnect and reconnect job. Disconnected al cables (one at a time) and reconnected a couple of times.. Success was mine
My 8.1L Vortec (Engine) had to be replaced,,, Well it would not start, Diagnosis and Error codes suggested a specific sensor.. The engine was used had sat for like a decade and the terminal on the connector on this sensor which we reused for reasons I need not explain here (Other sensors we used the origina engines) so the mechanic unplugged and re plugged a few times And I tried again I dont think I got the key all the way to the start position and it was running (fired on the first cylinder to reach TDC).
So that would be suggestion 1
NORCOLDs have undergone a recall. Many of them have a "Recall box" This is a black box with a red light.. Ran into a RVer last summer who's Norcold was not working, He described it and mentioned the light was on (The box is clipped to a pipe in the outside compartment) (I took my big magnet and waved it across the top half of the box. there was a CLICK, the light went out and the fridge now works.. HE,,, Went out and bought a magnet.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times