a/c is only run on 120v.
refrig runs on propane/ 12v / or 120v. Refrig has settings.
Lift motor and pump only work on 12v.
The battery needs to be good and fully charged.
I have a 1985 and it works well. Grounds and switches/fuses and battery are main culprits when issues.
The a/c has a dedicated plug in for the 120v source.
Check the fuse box when plugged into 120v and determine that the power is present.
Then check the converter to make sure it is changing power to 12v for lights and charging.
The lift motor will not work with out a strong 12v battery. I don't like to jump mine from the TV.
If it worked a month ago it is something simple, that you haven't found yet!