Dometic 2554 3-way (No AC power?)

[6jdad]

Dometic RM2554 3 way fridge:

We always plug in 15 amp at home to cool fridge and add food before departure, then allow the switch to DC while on the road, then back to AC when on shore power (30 amp) at destination.

Once we arrived at destination, we no longer had AC - fridge would not switch over on shore power and the converter ran most of the time on DC (probably should have switched to gas, but was conserving propane).

I checked the outlet where the fridge plugs in and it's fine.
Both glass fuses on the lower board are fine.

Any suggestions for next steps?

Thanks in advance! (I do have a nice multimeter and I'm mostly capable of using it)