Vent problem

[alrhoads]

For starters I want to say hi. This is my first post on here.
I am working on a 06 E450 diesel and the vents have stopped working. I have checked the vacume pump and it works, I have vacume to where it goes down the fire wall and I lose it there.
I can not see where it goes, but I see where it comes through the fire wall on the pas side at floor level and I have no vacume there. I am not sure what to do at this point other than remove the heater core and box to get to it, do any of you know of a better idea?

 

[DaveBen]

I am guessing that you have ESOF (Electronic Shift On the Fly). Better check the vacuum lines going the the hubs. That is usually where they leak. airhoads.

Dave

 

[alrhoads]

Sorry for the confusion, this is not my truck. The ambulance at the fire station has the problem, and they always ask me fix things.
It is a E450 van and is 2wd.

 

[DaveBen]

You have got me...

Dave

 

[alrhoads]

I can see that the vacume line goes down the wheel well twards the fire wall, but I cant see if it goes anywhere els before it goes through the fire wall. The leak would have to be where i cant see it, I just dont know what all is down there if anything.