05' Ford defrost issue

Well i am hoping some of you guys can help me out here. I've got an 05' F-550 powerstroke and the air system is stuck on defrost. The dealer told me that it was probably a vaccum leak somewhere but i can't seem to find anything. If anyone has some insite i'd appreciate it. When i started to trace the vaccum lines i did find that the grey line under the hood was unhooked and now i'm not sure of where it goes for sure.

Ya i traced all of the lines the best that I could. Everything seems to be in order, but i must till be missing something. It's my work truck so I think it's going to the shop on Monday. I'll have a little more time to mess with it on Sunday so i'll go over it all again. Thanks for the input.