It was clean under the cover what I found is it cools just fine but the duct work is not designed very well almost all the air is pushed to the rear of the coach. If you close off the ducts under the AC unit and force the air through the ducts most of the air goes to the rear of the coach leaving the front portion with that huge window very hot.
I am going to design a new vent cover that I can direct more air forward. I machine plastic for a living so I will just make a nice new vent cover for the inside that has some vents to push air forward.