Help with Change-over valve vacuum hoses

Guys I took out my expansion tank and the fuel filter on my 1999 C4 and I noticed this little check valve that is above the alternator and the vacuum hoses came loose. There is one normal sized vacuum hose that is still attached. The thing that is confusing me is the other nipple has a normal sized 2� length vacuum hose attached to it. And there is also a harder and much thinner plastic line that I assumed goes into the nipple. So my questions are: 1. Why is there a 2� vacuum line there? Is it for a protective sleeve for the thinner plastic line? And I am assuming the thin plastic line goes into the same nipple? I can see that this line went into the nipple due to a portion of the line looking clean and new as it was not exposed to the engine heat and grime. 2. Where does this valve attach to? I should have taken a picture of it before but I didn�t really notice it until now. Does it attach to a bracket? Or does it just lay on top of the alternator? I see the valve has a clip to attach to something but can�t figure out where. The valve in the picture is lying between the air injection hose and the alternator and the small thin plastic line lying on the right side of the alternator just to the left of the yellow dipstick.

[QUOTE=rhkwon;15831079]Guys I took out my expansion tank and the fuel filter on my 1999 C4 and I noticed this little check valve that is above the alternator and the vacuum hoses came loose. There is one normal sized vacuum hose that is still attached. The thing that is confusing me is the other nipple has a normal sized 2� length vacuum hose attached to it. And there is also a harder and much thinner plastic line that I assumed goes into the nipple. So my questions are: 1. Why is there a 2� vacuum line there? Is it for a protective sleeve for the thinner plastic line? And I am assuming the thin plastic line goes into the same nipple? I can see that this line went into the nipple due to a portion of the line looking clean and new as it was not exposed to the engine heat and grime. 2. Where does this valve attach to? I should have taken a picture of it before but I didn�t really notice it until now. Does it attach to a bracket? Or does it just lay on top of the alternator? I see the valve has a clip to attach to something but can�t figure out where. The valve in the picture is lying between the air injection hose and the alternator and the small thin plastic line lying on the right side of the alternator just to the left of the yellow dipstick. [/ QUOTE]

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Here is a pdf file

Quotes source post: 15831673

Is #19 & 20 a one or the other item?

I saw the same diagram and I couldn�t make any sense out of the vacuum lines as they pertain to my car. I�m sure the valve is # 18 but there are 3 of the same valves. I think the one I�m talking about is the one attached to the hose # 12 which in turn attaches to hose # 28. Very confusing.