Originally Posted by 16ACE27
Sounds like it's freezing up the evaporator overnight.
Basically reinforcing this response.
Your AC is freezing a block of ice blocking the air flow.
IF it runs continuously without cycling, it does not have any time to thaw the frost that may be developing on the cooling coils. This is a particularly perplexing problem in humid climates and when it is challenging the capacity of your system.
AS others said, turn the thermostat to a warmer temperature (so the compressor can cycle). If you cannot get your RV cold enough this way, then maybe you will have to find ways to reduce the cooling load demand (insulate windows, seal cracks, etc.)
By the way, this is not unique to RVs; my house AC will freeze a block of ice and nearly block the air flow also.
And systems that are on the low side of normal for the freon charge pressure are more likely to freeze also.