wow.
So many posts to just replace it, or don't and put in a portable a/c??
The are NOT cheap to replace.
If I just up and replaced my RV a/c every time it went on the blink I'd have replaced it 6 times. :R They CAN just be in need of repairs.
It can ice up, dirty coils, etc. All that can be fixed.
Call a local RV Mobile Repair. Find a close CG and call and ask the manager who they use for RV Mobile Repair.
They will come out right where you are at most likely within hours. Even if it is at your home they don't care. My bet is They will diagnose the problem in less than 5 minutes they see and work on thousands of RV a/c's. Affordable, real competent and professional RV mechanics.
Also check your coach battery. A/C needs good strong 12 volt for the thermostat to work.