I have spent several hrs on here looking for the possible answer to my question. It seems this is a common problem. A/C will only blow thru defrost vents. This happened to me the other day. So today I checked under the hood and found this...see pic. I have the probable answer, break in the vacuum line. My problem is I have no idea where the other end of this line is supposed to go. Any help would be appreciated. Pics would be fantastic.
i figured out my problem, here was my solution in case it helps anyone else out.
on the firewall passenger side where the gray vacuum tube runs into the firewall grommet there is also another hole for the black vacuum tube( my pic ) in the same grommet. since my black tube had fallen completely out of of the firewall grommet i couldnt tell were the end of my mystery vacuum line went from my pic. after enough poking and searching i finally saw the other empty hole in the firewall grommet. it was nicely hidden by some gunk build up. i pulled out the grommet, which was actually a mistake because the grommet has 2 connectors built into it. when you remove it, it pops the tubes off from the inside of the firewall since there isnt that much slack in them. and if you have big hands it gets alittle tricky to get them back on so use caution. once i plugged everything back up, grey and black tubing the a/c works fine out of the vents correctly.
"I have spent several hrs on here looking for the possible answer to my question. It seems this is a common problem. A/C will only blow thru defrost vents. This happened to me the other day. So today I checked under the hood and found this...see pic. I have the probable answer, break in the vacuum line. My problem is I have no idea where the other end of this line is supposed to go. Any help would be appreciated. Pics would be fantastic."
I have the same issue. Where does the gray vacuum line connects to? Does the black vacuum line connects to the one located at the firewall? Your answer is appreciated.
where do the gray and black vacuum line from the fire wall connected to. Both line have been cut clean. FYI both lines are coming from the firewall, just don't know where they are connected to. Your help is greatly appreciated. (2005 Expedition 2WD 5.4L)
Maybe cleaning those battery terminals might help too.
Bob and better half
As my brother reminds me regularly... "Life is not a spectator sport."
2007 F-250, PSD, SW, CC, LB, 2 WD, 85k, coolant filter, DashBoss, 1999 Expedition 5.4 322k plus, 32' CrossRoads CrossTerrain 5th wheel Toy Hauler, 24' Chaparral Villain lll 598 ci
Got busy last night before heading to work and forgot LionHeart. I have no idea if these pics will help you, but with the weather so cold, I was a bit leary pulling on the nylon vacuum lines.
Let me know if this helps.
1992 F-150 I6 4.9L 300 110K 4x4, SuperCab, Manual
1992 F-150 V8 302 156K 4x4, SuperCab, Auto
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The small black line feeds TO the climate control system, so it should be going INTO the firewall from the engine bay. The grey slightly fatter line feeds to the hot water control valve there in the heater hose line of the engine bay. I would assume you're having all kinds of climate control issues as well.
You should see the grey vacuum line plugged into the hot water valve here....
Take a LED flashlight and look on the firewall right in that area, you should see a pair of vacuum lines like this .... small black one, and fatter grey one....
In your second picture the line plugs into the fitting facing forward. The other place does not get a vacuum line as it looks like it is part of the arm controlling the valve.
98 XLT 4X4 5.4 W/aftercooled Vortech S/C, custom tuned w/lightning maf and 42# injectors, Flexlite electric fan, Lightning Head and Marker lights and LED tails, Bilsteins, S/S headers and Magnaflow catback, Pioneer nav system and Airlift rear bags w/compressor
Thank you all for the reply. The above photos shows how it lookes like on my truck.
The Grey line goes to the hot water control valve. Look at the pics I posted. Somebody butchered your setup.
Yes, the black line goes to that pancake looking check valve fitting you are pointing at. You'll have to get some vacuum tubing to make up the connections.
Nothing goes on that other white line plug, it should just be there to seal the line, it should be sealed if it is not already. Put a cap on it to seal it.
There should be no vacuum leaks in any of the lines under the hood !
Who the hell's been under the hood of your truck ?
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