Still need help with vacuum problem for vents

[94kingcbra]

Ok I know many of you have had this problem and fixed it. The vent portion for my heater or ac is still not working. Everyone reccomends to check the vacuum tree on the drivers side firewall. There is supposed to be one line that comes from the engine compartment, to that tree, then to the hvac controls that controls the defrost, floor, and instrument panel vents. Now according to this diagram I found that is supposed to be for 88 - 95 5.0's, that one line that goes to the hvac is for all the different controls, and it's the hvac that controls the individual vents. Can anyone else clear this up for me, maybe I am looking at this wrong. Thanks

[attachment deleted by admin]

 

[eliyarbrough]

I wish I could help you! One of mine was just collapsed, so he knew it was that one! It took the guess work out of it.

 

[94kingcbra]

I've been studying this diagram and if you look at where the panel/defrost door vacuum motor is, the door will open for the instrument panel vents when vacuum IS applied. Then if there is no vacuum it will go to defrost only. Now doesn't this mean that if there was a vacuum leak somewhere, then the defrost wouldn't work and the vents would only work???

 

[5litrarag]

As far as I have investigated on my car the problem was caused by the vac. line that goes from the tree to the firewall was broken.
I replaced that little hose and the vents worked again.

Looking at that diagram it appears that yellow would the line to look at inside. However on the 94-95 cars that thin vac. line under the hood is the most common issue.
You can't miss it, its the thinnest line that comes off the vac. tree. 1/8 inch diameter black tubing....

 

[CC'S95GT]

your defroster vents are spring loaded, when vac is applied it closes the defrost vent and opens the dash ones. like said by 5litrarag it's the smallest tube on the fw. mine was broken right in front of the passenger behind the heater hoses

 

[94kingcbra]

I am still trying to fix this....I have looked at that little black line and it is fine. I traced the tube through the firewall, and into the dash. I pulled the glove box and pulled apart the vacuum connection (which is the last joint I can see from behind the glove box) where the lone black tube joins the rest of the vacuum tubes...I tested the vacuum there with with my vacuum/boost gauge and it is the same as the other vacuum lines that run to that connector. I also blocked it off to see if I could hear any leaks in the line between the tree and that point and there were none. So now I am thinking that there is a leak or a blockage between that connector behind the glovebox and the actual vent control box. Now, does anyone know where exactly the vent control box is in my dash? I don't want to have to take apart the whole dash if I can reach it behind my cd player or something. Thanks

 

[94kingcbra]

Anyone?

 

[CC'S95GT]

these things are really hard to trouble shoot without being there. if your really sure all the vacuum lines are good under hood and you feel like the controls at fault. i would pull the radio bezel off and go from there. the radio will need to come out too. do you still have the oem radio or aftermarket. you'll need a special tool to release the oem radio from the housing and hopefully you'll be able to see enough from there. good luck

 

[94kingcbra]

I know the vacuum line is good until it goes behind my dvd player. My question is,where is the unit that those vacuum lines go to, is it accessible from behind the cd player? I want to test the actual doors that open and close that are vacuum operated. Again, the small black tube that comes through the firewall has a spot that I can disconnect behind the glove box. That's where I tested it, and it was fine. So where does the other end of this black tube stop. It goes up behind my dvd player to somewhere I can't see through the glove box. I don't want to have to remove my DVD player to find out it's behind my cluster, if you catch my drift. I appreciate your help, Justin

 

[94kingcbra]

Anybody? I'm going to the bar now:hppyhr:

 

[94kingcbra]

I figured I'd bring back this thread because I finally got the chance to track down the problem since I moved, and the previous threads are where I left off.

I pulled out my center console and I found a leak where all the 4 vacuum tubes go into the back of heater control knob...Is this normal, because I noticed that only the black tube has vacuum coming from the motor, and the white hose goes to what looks like a solenoid and it gets its vacuum through the plastick connector. This is where I hear the leak coming from, and no matter how much I wiggle it I can still hear it leaking.

So, I pulled out, and now I am in the process of finding one that still has the vacuum hoses connected. While I wait, is there any way I can test this swicth...? Tommorrow I'm gonna remove the hosing that was connected to the control knob to see whether it is loose tubing or the part itself...Let me know if you know anybody has a working control knob with the hose connection still intact and never removed from the control connector...Thanks,
Justin

 

[94kingcbra]

This is what I am talking about....

[attachment deleted by admin]

 

[94kingcbra]

^ ...does anybody know how to test this thing?

 

[CC'S95GT]

i have no idea without having it in my hands

 

[94kingcbra]

those are the vacuum lines that it plugs into, and I can hear a leak in the connection...On top it has 4 electrical wires, I can get the colors if that would be helpful....

 

[94kingcbra]

and here's what looks like to be an accurate diagram, can anybody else verify this?

[attachment deleted by admin]

 

[94kingcbra]

should I follow the yellow one or replace the switch first...? I am thinking that if I apply a vaccum straight on where the yellow tube connects to where door is, it should work...? I need some help guys..thanks

Justin

 

[94kingcbra]

I am going to replace the switch and lines tommorrow hopefully...I found a ford recycling center that has a mustang with the heater controls still intact....If this doesn't work then it looks like I will be replacing this...

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=280297917579

How hard would this be by myself? You can see in that 3rd picture the silver canister...That is what the yellow tube connects to, which in turn controls the door that operates between the defrost and vents...

And if that don't work I'm screwed I think...

 

[CC'S95GT]

looks to me that if you apply vac to the black hose and cycle the sw you should be getting the air sucking into the other 4. i would think blowing into the hose would work too but idk. another thing on the diagram by the flaper doors you see a V and a NV, v-would be with the vacuum on and of course, nv-would be no vacuum. that is why you would get the defroster only with a vac leak. hope this helps some

 

[94kingcbra]

well the black hose already has vacuum, so all I did was apply it straight to the yellow tube by by-passing the connector...Still the air blows out of the defroster...So do ya'll think this means my vacuum motor that contols the door is broke...?