That RED light on SOLID (Recall Box) indicates the Stack High-High Temp Sensor has tripped (700*F)
When tripped ALL DC to fridge shuts off
So either the cooling unit has a 'Leak' (check for any yellowish residue in/near burner area or ANY place on tubing.
THAT means DEAD
No signs of leaking......
Has it Rained?
Have you washed the RV recently?
Water can 'short' the Recall Box little circuit board/sensor wiring etc
Hair Dryer to rid the box/wiring of moisture then Tilt Box more downward so it is less susceptible to moisture
Could just be a faulty Recall Box circuit board....most current version is 'E'
* look thru small opening on front of Recall Box and check which version you have ---if not 'E' contact Norcold for upgrade
IF not an 'E' the lower versions may/may not reset using the magnet
Strong Magnet held on face of Recall Box near top and then slowly move back/forth until you hear a CLICK and RED Light goes OUT