Help-Problems Engaging '94 Ford Explorer 4x4

[getwood4]

I have a 94 Ford Explorer. My 4x4 indictator lights are working when I push 4H and 4L, but the 4x4 is not engaging. I even hear a 'click' when I push them. On the transfer case there is what looks like a 5/16" male vacuum fitting. Is this a fitting for a vacuum line or just a vent. If it is for a vacuum line coming from the transfer case, where do I run it to? Could this be my 4x4 engaging problem? Any other suggestions would be helpful! Thanks for any help!

 

[Rick]

Lot's of good info here: http://www.explorerforum.com/Singleton/web/pages/tcase.html