Any ideas what this hose should be hooked up to? I'm guessing it is not super important, because I have been driving with it disconnected and ran through emissions this morning.

 

Its a 1992 4.0l. The hose looks like it runs into the firewall, but I cant really tell.

 

if it's running into the firewall chances are it's a vacuum supply for the climate control... do all the modes and settings work when you change them?

 

or could have been for a heater control valve that a PO may have removed.

 

Heat and A/C both work fine. I just can't figure out where the hose should connect to. The end is split which is why is probably fell off.

 

is there a a heater control valve in one of your heater hoses that you can see under the hood... they tend to self destruct and is not necessarily a needed part so some people just opt to run with out. are you sure it runs IN to the firewall and not just along the firewall.

 

it looks like the hose thats running along the wiring harness just above your finger in the picture looks like it's newer, is it possible that it was run to replace the hose in your hand???? hmmm ,probably not, that would be too easy though... lol.

 

So one end is disconnected? Where does the other end go.
I'd say that hose was to originate at a connection to upper rear of your intake manifold, a vacuum hose, then it travelled along firewall to passenger side inner fender and forward to the vacuum accumulator (little plastic pig) mounted behind and below passenger side headlite area. Check if someone hasn't replaced it in the past. If both ends are disconnected and your running, pull it and discard.