Working on it and now the A/C stopped working?

Well, I finally found some service info on engine temps and the warning messages, according to this you were receiving the Engine High Temp message because the coolant temperature was getting above 260f, and being below 255f is apparently within normal operating temperatures, which is why the message turned off, seems very high to me,
And 269f is where you will get a critical high temperature message.
The gauge on the Cluster reads 100-260f, that's its range, still you shouldn't see the ECT glitching out, But I guess 220 is within spec, that explains why you aren't seeing the fan on High at that temperature.
Are you still seeing the coolant boiling in the reservoir?

Okay, well, if you do decide to change out the ECT sensor, just make sure you get an OEM one from the dealership, or rockauto carries OEM parts a lot of the time. You can flush the radiator too, coolant systems build up an acidy type of sludge over time which is what causes most heater cores to eventually leak, so it's good to flush them out with just plain water once a year, I know it's cold where you are now, so that will have to wait, but just things to keep in mind. Hopefully things will be ok over the winter for you, we haven't really gotten into the cold days yet down here. So I'm still working outside on mobile calls.