It has already been mentioned but here ya go again. It goes to the tranny breather on the top left hand side of your motor. You will have to take the plastic and fuel tank off to get there. It runs down the left side of the frame and just sits there. It doesn't hook to anything, just zip tied to the frame.
EXRIDER. Have you stripped your quad yet looking for places to plug it in? If not, you need to. It only has a few places to go. If the T under the air box is full then you only have 1 more place to go. Thats where I told you. Just take your rear plastic off, take the fuel tank off. then you will have much more stuff you can look at. If you do that I promise you that you will see where it goes. You have spent a whole lot more time on these boards asking about it than it would have taken you to take the rear plastic and the fuel tank off.