I don't recall seeing this open space before. It's on the drivers side under neath by rear door inside frame rails.2006 ram 1500 5.7 hemi

 

I don't see an open space. I see something that looks like a brake proportioning valve or part of the ABS system. What open space are you referring to?

 

Whatever that thing is, it looks like there should also be something else there where the hoses are. Not sure how else to explain it. I left my car at a valet airport parking and some were thing happened to my truck and I'm very suspect is all.