Air hose purpose 2003 EB

[Norexpy]

Hey guys!
Just replaced the thermostat on my 03EB. Looked for signs of leaks after words, and heared a whistling sound by the battery. A small air hose is open and it sucks air. Seems to be broken off from a rubber attatchment, but can’t figure it’s purpose. It goes to a two way splitter, and continues to a sensor of some sort - and to the air intake and ac as far as I can tell. Tried to cover the hole with a finger and it seems the engine settles down on idle, and the exhaust seems to have a different look with less smoke. Runs cleaner. May be my imagination. Does anyone know if it is supposed to be open like it is - or if is meant to be connected somewhere? Added a few pictures. One has the Ford part code I think.
Thanks in advance from Norway.

 

[whtbronco]

That should be connected to the vacuum reservoir. It's a small plastic molded box behind the battery. Pull the battery out and you'll see it or use a mirror and you might be able to remove the other half of the connector hose and replace it. I had the same issue recently I used a small piece or spare tubing I had laying around to repair it.

 

[Norexpy]

Thank you!