help with vacuum line please

Hi first time on here I just replaced the intake gaskets on my 99 windstar and noticed at the rear on the engine I have a line that is open with nothing going to it and it does leak vacuum it comes from the pass rear on the intake and goes back then into a tee and one line goes through the firwall with the heater hose and the open one just has a elbow with nothing but looks like a line should plug into it. I have looked all over for somthing to hook it to and have failed to find anything and have not beed able to find a schmatic for it I will thank anyone that can help me with this

I think there is a vacuum accumulator, a black box that holds vacuum for when the engine is off to provide vacuum to the hvac inside. I think it is located (facing the eng compartment) on the left side behind the strut tower under the cowl. It's a tough place to see or do anything. That's a first geuss off my cuff. Hope others will chime in with better.

If it's a rubber T that connects to a vacuum line going into the firewall towards the passenger side, it should connect to a vacuum connector on the heating and a/c plenum on it's right side almost against the firewall. It's almost impossible to get to unless you've got the wiper assembly and all the associated plastic removed.

hi, yes I had the same thing... it goes to a black box behind the strut tower on the passenger side...you will have to remove the crowl to see it I bet your heater controls quit working as well.they will start to work when you reconnect the hose,,, I put some glue on mine when I reconnected it so it wont come off again....

I found mine off the accumulator too, but interestly someone had installed a screw into the end of the hose instead of just reattaching it to the accumulator. When I was working on the P0174 fix I found this and repaired it.

The vacuum from the manifold goes to a T that is also a check valve. So if any of the three lines at it is disconnected, you will loose your vacuum controls with your hvac and have hissing and engine problems. Plugging just the reservoir line will allow you to operate the hvac, but not enough for all situations where you have low or no vacuum. The check valve enables vacuum to be stored in the event of those conditions, especially when the engine is turned off. A similar setup is used for the vacuum assisted brakes if the engine were to turn off unexpectedly.