It's easy to see if your AC element is operating. You have to isolate it from the fridge's system.
1. locate the element in the boiler section of the fridge. It is a 1/2" or so L-shaped rod with the long section buried in the boiler and the short section visible.
2. locate the 2 wires coming from the element and follow them to the control box.
3. remove the wires from the control box.
4. make a pigtail (usually with 2- 1/4" male spade connectors) with an old extension cord (2-wire is fine). Attach the connectors to the cord. Polarity does not matter here.
5. plug in your extension pigtail to a known working 120VAC outlet. Let the fridge run overnight.
If your element is OK, the box will be VERY cold when you open it.
You can also do a continuity check of the element, but Dometic prefers to do the above procedure as a fool-proof verification.
Good luck and be sure to report back with your results.