Looking for advice on best way To keep large toy hauler cool

Even with my AC vents left half open, I am freezing up. I have had two RV shops look at my AC's in the past year and a half and both say they are working fine but with freeze up in hot humid weather. I had knee replacement last year so crawling is a bit of a task. I will try to get up on the roof today and check for any plugging. We do have quite a few trees in our yard and get quite a bit of pollen/tree debris in the spring.