Unknown lose wire in engine bay?

[ExploderTrouble]

Hello. Yesterday when I was changing oil and air filter, I noticed a loose hanging wire in my engine bay. The first half of it is grey in color and goes to the passenger side firewall. It has a plastic connector with a black wire connecting to that grey wire. The end of the black wire isn't connected to anything and is the one hanging around the engine bay.

Any idea what this wire should connect to? 05 4x4 XLT. Bought used but I've had it awhile. Stock everything including radio.

http://i.imgur.com/xJYCN1F.jpg
http://i.imgur.com/yfBFeOk.jpg
http://i.imgur.com/ZP7u8tN.jpg
http://i.imgur.com/gvWADbz.jpg
http://i.imgur.com/u0qXmLU.jpg

 

[swshawaii]

Vacuum Reservoir Lines

http://www.explorerforum.com/forums/showthread.php?t=439184&highlight=vacuum+reservoir

 

[ExploderTrouble]

I've read the other thread. I see the vacuum reservoir under my glove box area, but still can't figure out where to connect this line in the engine bay. What does the area look like in the engine bay to connect this to?

 

[mbrando1994]

When doing my valve cover swap out I too noticed this line was loose in the passenger side bay when reconnecting everything, took me all night to find where it goes. Look deep into the bay lower down maybe mid engine block and look for a little black nipple that the connector would fit on to. I don't remember exactly where it was I apologize. It definitely should connect to something and I do believe it is related to the vacuum reservoir.

Here is a diagram of what you may be looking at. It's for a 2004 explorer but I would look for a small connector in line with one of the heating hoses. Worth a shot. (Number 11)