No air line to fan for long time

[tree98]

I bought this truck used 4 years ago(2007 T800 cm870). I'm currently putting a new fan blade and metal shroud ring on it. While poking around the engine I find the air line going to the fan clutch isn't hooked to anything! It's just hanging there. It didn't come apart on it's own, the previous owner had to of knowingly unhooked it. Strangely the fan seems to work just fine though, the fan light comes on in the dash and you can hear the fan come on, light goes out fan turns off. Engine has never gotten hot. What am I missing here??