1991 Wagoneer - vacuum leak sound under dash
I have a vacuum leak sound under the das, right behind the 4x4 lever. I haven't take anything apart yet but from what I can tell, there is a little black box (relay?) with some wires connected to it. It is screwed against the dash. As I pressed he'd against this "relay" it appears that the vacuum leak sound is reduced. I assume this has to do with the 4x4 system, which does not work. Any suggestions, ideas of what my problem is?
I am new to this vehicles and I am not familiar with this vacuum system.