Designer 35RLTS and Jayco Talk...Thanks Frank!!

My old TT did the same thing. Remove the a/c cover and you should find 4 bolts one on each corner. Tighten these 4 bolts. They have become loose and is allowing outside air to enter freezing up on the coil. I noticed that there was no air coming out of the vents on mine and called the dealer right then. They told me what it was and it fixed it.