Hi folks, a few days ago my vent control started going wacky, and I could hear a vacuum whistle under the hood. I traced it to this T fitting just behind the battery box (between the battery box and firewall). It appears it should be connected to another line, or perhaps capped? I've looked everywhere around it and can't find any disconnected lines.

It's a 2005 Expedition.

Many thanks in advance !

 

Hmm, being white I don't think that's an OEM fitting. I'm sure it's a repair, and like you suspected a cap fell probably off.

 

Well, I think it's factory, as there is another T just next to it that leads down somewhere else. All the connections look "factory" and as the original owner, I know I've never had any work done that would have involved this.
The pic below shows another angle where you can see the other T (black) just next in line to the white T.

On a side note, I temporarily plugged that white T and the vent control seems to be working fine. But I'm not sure if I've left vacuum off for somewhere else by capping it.

 

Does your 4WD work, I don't mean just does the dash light come on, I mean do you actually feel the 4WD working? The vacuum actuator down on the front differential is the only thing I can think of with a hose that big up there.

 

I don't have 4WD in this Expy, so perhaps that's the vac line for the ESOF 4WD models? If so, then it would have been capped on this 2WD.

You very well could be right, as I've had vent problems in the past on my F250 when the ESOF vac line had a leak. Didn't remember that they offered the Expys with 4WD.

 

I have taken my 2005 expedition in to have a fuel system cleaning done.. I have taken it to two separate places, and neither can seem to find the intake vacuum line that is needed to do this work. Any ideas as to where I can obtain a diagram, and or instructions as to where this valve is, so as to be able to get this service done on my vehicle..

Much appreciated in-advance.

 

If you're looking for the fuel pressure regulator vacuum hose it is on the fuel rail above cylinder #4. If they just need a large vacuum hose then they should use the one going to the brake booster. However, IMO if a shop cannot find something as simple as either of these vacuum hoses then they are a pretty lame shop and I would be highly reluctant to have them touch my vehicle.

 

First thank you for your response, and second.......... I was having just that very thought. I thought at-least I would try to find out where it was located. At worst I might-could figure out how to service the fuel system myself.. Thus wouldn't mind finding a diagram.