taddyport just made me remember an event we had with our previous camper. For some reason, it quit blowing cold air, but it was blowing. If I remember right, in desperation, I posted for possible causes on these forums.
Someone suggested that maybe the fins (the thing that reminds you of a radiator inside your car) might be iced over. If the weather condition are just right, it's possible the air conditioner is kicking out so much cold, and condensation on the fins is freezing before it has a chance to evaporate. As it get's colder and colder and more and more condensation building up, the fins can actually ice over and block all (cold) air flow completely.
So I pulled the sponge air filter cover and could see the fins, and sure enough ... there was a good 1/2 inch white ice built up over the fins. The solution was to let it thaw out and melt all the ice away (which didn't take long with the heat we were experiencing).
Once all the ice was gone, the answer to keep that from ever happening again was to start the air conditioner at a higher temperature. Turn the thermostat down to where the air conditioner "just" turns on and no further. Let it cool to that point and wait for the air conditioner to turn off. Wait a minute so the air conditioner can recycle, and then turn the thermostat down, just a pinch until it turns on again.
Keep doing this until the temperature in your camper is where you want it.
If the air conditioner runs constantly for a long period of time, the ice that builds up on the fins never has a chance to melt off. The air conditioner needs to cycle on and off so warmth and evaporation will keep those fins from icing over.
After that one-time experience, I've never just turned the air conditioner thermostat on 70 degrees when the outside temperature was 90 and the inside temperature was 100. I've always brought the temperature down slow this way, and never had a problem again.
By the way, in our house, we have 2 central air conditioners. Both coolers are in the attic. A couple years ago, one of them started blowing hot heat. I remember the experience with the camper and opened up the return vent in the ceiling, looked up there and... and sure enough ... fins iced over about an inch thick! It was a fluke, but it does happen.
Not sure if this could be your problem, but it's also something worth exploring.
