05 jeep wrangler heater is only blowing for the defrost no matter what setting you have it on?

Just fixed this problem last week actually. (wrangler 05) i went to jeep, the guy showed me how to fix it for next time. Jeep's a/c and heater's default is the defrost. The system works on a vacuum, the cruise control works off the same line as well. With my understanding they are the two things that use the vacuum system.There are several places that it can come lose at, and can be where the two previous people stated above. It is a VERY common jeep issue. But, when the hood is lifted start at the cruise control and follow the hose. The two join together and both are connected. At the end there is a little rubber elbow piece that connects the hose to the engine area (i wish i could remember the proper name). thats where mine came off and continually does so. it gets carbon build-up very easily, they replaced the little rubber piece and i was good to go. But, usually its a very easy fix takes 5 minutes. i am hoping since its the same make and model your problem will be there as well. Second time it's happened so i asked how to fix it :)