found this n another site:
The cooling system of a RV fridge works the same on either propane or shore power:
A heat source(a small flame on propane, an electric heating element on shore power) heats an ammonia based refrigerant. This hot, pressurized substance flows through coils and small oriffices and looses pressure, absorbing heat in the process.
If the fridge works on propane, this indicates the cooling system is functioning properly.
I would suspect the electric element has failed. It can be found near the burner assembly. It has two rather large wires and is mounted in the chimney.
To test, disconnect power (unplug 120 plug from the outlet near the fridge) and remove the element leads from the control board. With a volt/ohm meter, test across the leads. There should be 40-50 ohms, if the meter shows no ohms, the element has failed.
If the element does show 40-50 ohms, the problem is probably the control board relay.
2019 FR3 33DS Motorhome
650 Watts Solar, 400Ah Lithium Batteries, 2000 Watt Inverter, 40A DC/DC Charger, Sumo Springs, Roadmaster Steering Stabilizer, Blue Ox Trac Bar, Trauma On Demand Water Heater, NVIDIA Shield TV,