If it is low on refrigerant, It is not worth trying to repair it properly. Just get a new unit.
Lauren, how many units are on the RV, one or two?
Mike, not to get in a pi$$ing contest, yes a compressor can go bad, but you should know piston compressors have not seen much use in small hermetics for some years now. As to harsh conditions, the RV units are designed to operate on a wide range of conditions on an RV.
I have worked in Industrial refrigeration since 1970 and have done a fair amount of design and service related work on all sorts of and sizes of units. I am a mechanical engineer with a PE license and specialized in applied heat transfer and thermodynamics. So, I have plenty of experience and well versed on A/C as well as refrigeration.
The biggest problem is the indoor (evaporator) coil. Just cleaning the outdoor coil (condenser) is only doing 1/2 of the job.
Mike sorry, but your response was incorrect.
Ken