1996 vacume lines

i need a favor from someone with a 1996 or one that will have same vacume i have a picture here i need to know where this vacume goes.. i was having problems with my 4wd engaging the main vac was off on the actuator under the battery still didnt fix it so i searched more and found this loose and plugged it with a screw this morn and 4wd started working so i think it might be 4wd related? not sure.
anyway here is pic if someone might look for me
thank you guys

http://i18.photobucket.com/albums/b117/slreno1217/100_0102.jpg

omg!!!! roflmao

sometimes it takes a picture to see what your missing!

if you look close you will see a vacume ball of some sort at the top right.. it came loose from there heheh gees how could i miss something so obvious.

what exactly does this vacume ball do and what could it cause. because i have been having some problems with the truck not wanting to start cold would this cause that? i dont know how long this has been loose.