Why doesn't my AC work in my 2000 Jeep Wrangler?

Did you try putting some freon in the A.C system or check to see if some was in system ? Will not come on if there is no freon in it

I believe what Firebird 338 means is R-134a... freon is illegal for most people to buy, but most people still call it that. No biggie, but he is still correct that without the cooling agent in the system (from a leak) the AC clutch will not kick on. That is very likely the issue. If you have not worked with R-134a before I would not recommend it. You are only supposed to charge on the low side, the vehicle needs to be running, and you need to assure that you don't have leaks. As much as I know, I still have someone else do my AC, because I don't have equipment to search and seal the leaks if any, or a place to properly charge and balance the AC system. You've done all you can, sometimes we need to bite the bullet and differ to someone with more experience on the matter.