Ok here it is, I have owned Eight different Jeep when I lived back east, and the AC only worked on my new ones. But in New England I never needed it. However the South West is a little different. Anything with Engines, Drive lines, Suspension, Electrical, I can do. I have no experience with ac and very little money because i'm starting school later this month for all things HVACR. I have an 88 XJ with 267k on the body, 75000 on the Engine, Trans, and T-Case. The AC was converted to 134 in May of 08, before I owned it. My problem is the compressor kicks on and stays running the high pressure side gets very hot, the low pressure side stays at Ambient temp, and there is no cold air. If it was low wouldn't the compressor kick on and off, or just not kick on. Where low side has no change in temp, is it plugged. The prior owner told me everything about the Jeep, he did not miss lead me in any way, he said it blew cold air. Thank you all.