i am new to these, i have a 94 GMC Jimmy, my 4WD was not working and i noticed that there was a vacuum line disconnected, i think it is working now but im not sure how to test it, anyone know how? also there was another plug where a vacuum line is supposed to plug in and i could not find a line that would go to it, so i need a vacuum line diagram, any help on these two problems would be greatly appreciated. i looked all over the web for a diagram but could not find one, thanks everyone