Location of main HVAC vacuum line in cabin? 2003 Expy XLT with manual AC controls

[Pinky 1352]

Still trying to work out all of my malfunctioning AC issues.

Got parts replaced, now I need to address my temp control issues.

Where exactly under the dash does the vacuum line, that controls the cooling/heating environment, come in, and is it anyplace I can see without removing the dash?

And where is the main place it connects TO?

I've found diagrams for the vacuum lines in the engine compartment, but can't find specifics for under the dash!

I'm having an issue because at some point a previous owner must've rerouted things. The original very thin grey vacuum line that went from the engine compartment to the HVAC system was disconnected, but the AC system still worked.

It no longer does and defaults to defrost mode.
I'm guessing the mechanic that replaced all.of.my ac system hoses knocked something loose.

I figured if I could semi-easily backtrack from under the dash I might be able to figure out where something got screwed up and fix it or go back to the original layout.

I was hoping that I could figure this out without removing the dash and center console.


Any clues would be greatly appreciated!

 

[Hamfisted]

The supply line comes in through the grommet in the firewall behind the blower. In the engine compartment you will find it down below the PCM. Or follow the hot water valve vacuum line back to the firewall, it shares the pass-through grommet. On the Expies with automatic climate control the control solenoid is under the dash right in front of the center console and you have to remove the center console to access it. I'm not sure the manual head unit versions even use this control solenoid but if you have it, that's where it is.


The vacuum line with the shroud over it is the hot water valve line. The bare vacuum line is the system supply line. This grommet is on the firewall just below the PCM unit....





This is the system vacuum control solenoid on the Auto systems located just in front of the center console under the dash ....









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[Pinky 1352]

Yes, on mine there's a very thin, light grey, vacuum line that goes thru the firewall just to the lower left (looking from front of car) of the computer.

THIS line was disconnected at some point by a previous owner.

I'm trying to figure out what they replaced it with, because the AC/climate controls *DID* work before this current mechanic replaced the ac lines and other components in the engine bay.

I do believe that my model also has that ac vacuum control box behind that PITA to remove center console.

My question is, does the vacuum line that comes in from the engine bay go straight to that solenoid assembly, or is there some other point where the vacuum line attaches first?

I'm thinking that if it's supposed to go straight to the solenoid, that I can simply start over myself by fishing a small diameter vacuum line in from the engine compartment, thru the firewall in the same spot that previous owner fed a power line to an amp (that's in the rear of the vehicle), because it's easier to access than where the original vac line fed in.

From there, I'd still need to take the center console out, but I could then maybe just hook the vac line to port #3 in the schematic?
(I'm fairly certain, LOL, that this is the correct schematic for my car?)
Last question would be is if there's a check valve somewhere in there under the dash too , or if the second check valve on the line in the engine bay is all that's needed?
And is the main vacuum line ONLY supposed to go to the solenoid you show above or does it tee out to something else?

I hope that makes sense!?

Note in third pic..
When I got the car, the vacuum lines where already like this. The thin black vac line coming off main vac line was SUPPOSED to be connected to the thin grey line (that now has a screw inserted to cap off the end), at least according to schematic. Or, more likely, the grey line simply connected to that check valve.

That's why I believe that at some point they ran another vacuum line somewhere, although I'll be damned if I can find it!
My sneaking suspicion is that AC mechanic inadvertently disconnected that thin black vac line from whatever newfangled vac line goes thru the firewall to the dash.

 

[Hamfisted]

So it looks like your SUPPLY line is intact, and passing through the firewall grommet, correct ? And you're holding a broken and disconnected hot water valve control line in your hand, correct ? So you should find the attaching hot water valve line just inside that firewall grommet. You're losing your vacuum through that broken off hot water valve line. The rest of your vacuum system is probably still intact. The system passes 100% vacuum through that hot water control line, and when you want to warm up the cabin and move the temperature selector towards a warmer position the system starts to close off vacuum to that line and the hot water valve opens. It takes near full vacuum to close off the hot water to the heater core.







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[Pinky 1352]

There is NO second vacuum line that I can find going thru the firewall (or at least I haven't found it yet!).

I've always assumed there should be SOMETHING attached to that piece with the lever on that hot water line, but I never knew what's missing there!
I haven't found any pics that exactly match this engine and none of the expys that I looked at in the junk yard had this exact set-up either.

So, to recap, the ONLY vacuum line I've found is that very thin light grey one going into the firewall. The one that has the screw in the end of it, and has since I bought the vehicle!

To switch from AC to heat, I need to MANUALLY switch that lever in the hot water line to the front for AC or move it to the rear (by hand) for heat. (Any idea what that thing with the lever is called?)

The part that really puzzles me is that only after the other AC work was done does the climate control can not now switch off of air coming out of defrost vents!
(The AC *was* working prior but had a leak somewhere so we swapped out a bunch of AC lines, condenser, drier, expansion valves etc.
It's holding pressure now.)

From my very rudimentary understanding of how this system is supposed to work, it should never have worked at all with that broken vacuum line?
I can't fathom how that was bypassed and that's why I was looking for a second vacuum line somewhere!

If I try to connect the broken line from the supply into the grey vacuum line that goes thru the firewall the system still doesn't switch to AC vents instead of defrost vent.

 

[Hamfisted]

This is what really sucks about buying a used vehicle. When previous owners completely jerry-rig systems or wiring.
You need a new hot water control valve. Yours is missing the entire control diaphragm section. The shrouded vacuum tube you had in your hand attaches to that control diaphragm on the hot water valve, and the other end passes through the firewall grommet to connect to the control vacuum line.
Your system supply vacuum line appears to be intact and passing through the firewall grommet. If you find it broken in the engine bay side, repair it.










Motorcraft YG-368 Hot Water Control Valve....


Hot Water Control Valves at Rock Auto




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[Pinky 1352]

Well now, THAT makes much more sense!

Thanks for those photos.

BTW I spent the day getting the center console removed. I do NOT have a system control solenoid (or if I do it certainly isn't near the floor as I've seen in some videos.

The 2nd pic shows a connector (similar to a molex connector) that has the vacuum lines. This is under the driver's side of the dash. The end you can see goes back across towards the passenger side.

It's getting late, therefore dark so stuff is hard to see, but it *feels* like a bunch of them simply go up and into the rear of the temperature/fan controls? I *CAN* see that the black and white lines go up in a separate direction toward higher in the dash. The other colors seem to go behind the dials.

Looks like tomorrow's job is to get the darker part of the dash cover off so that I'll be able to access the temp controls.
That'll also give me a better view of what's going on in there.

It wouldn't surprise me at all that when the other owner installed the new fancy pop-up screen radio that they screwed up the original vacuum line!

 

[Hamfisted]

Try this test. When your motor is cold try rolling your dash temperature control all the way to the hot side. If your airflow returns to your normal vents you just need to repair the hot water valve vacuum line. The rest are Ok. Rolling your temp selector to hot closes off the vacuum to the hot water valve, and therefore the vacuum leak, and returns good vacuum supply to the rest of the system and control of your dash vents. Nothing invites trouble like a half-ass radio installation job.





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[Pinky 1352]

Well, that didn't work. Rolling it to hot did not change the air flow to vents, and to top it off, now when I do that I can hear the blend door actuator clicking.
I could swear this wasn't doing that earlier!

So now I guess I'm adding a blend door swap into this mess?
I've seen the how-to videos on that, done without taking the whole dash apart, and while I'm glad I have small hands it looks like that third rear screw is a real PITA to remove, and it's another PITA to get the stem of the actuator to drop back in correctly as there's not much clearance in there.
All this only made worse because I guess I won't know the correct actuator to order until I pull this one out because I can't seem to find exact specs for this particular build.


EDITED to add:
just so I'm clear, because there ISN'T a line in the engine bay that should've gone to the not water valve (which I ordered this morning. No one local shows it in stock or even order-able!), where does the line to it go once it's under the dash?
once again, these attached pics are the diagrams I found online that I *thought* belonged to this car? and these are the printed specs that came with them:

Port Hose Connections

Vacuum Application Chart — Manual A/C
Switch Port Color Function Function Selector Switch Position
MAX A/C PANEL PNL/ FLR OFF FLOOR FLR/ DEF DEF
1 White Recirc/ Fresh V NV NV V NV NV NV
2 Blue Floor/ Defrost NV V V NV V V NV
3 Black Vacuum Source V V V V V V V
4 Yellow Floor/ Defrost NV V V NV V NV NV
5 Red Panel V V V NV NV NV NV
6 Orange Panel V V NV NV NV NV NV

V = Vacuum

And Temp Control:
Item Part Number Description
1 18A318 Vacuum control motor — floor/defrost door
2 — Defrost air flow
3 18A478 Floor/defrost door
4 18476 Heater core
5 19860 Evaporator core
6 19805 Blower motor
7 — Outside air inlet
8 19A813 Air inlet door
9 18A318 Vacuum control motor — air inlet door
10 — Recirculated air inlet
11 18B545 Temperature blend door
12 18A559 Panel door
13 — Panel air flow
14 18A318 Vacuum control motor — panel door
15 — Floor air flow
16 — Vacuum from the engine intake manifold
17 19A563 A/C vacuum check valve
18 19A566 Vacuum reservoir tank and bracket
19 19A563 A/C vacuum check valve
20 19B888 Function selector switch
21 18495 Heater control valve

If I assume I have the correct data here, it looks like the heater control taps into line #9 which is the vac control motor for the inlet door?
Where under the dash is THAT located?
(it would really help if the schematic had mentioned the COLORS of the lines because that would make it easy to trace!
SMDH

 

[Hamfisted]

You'll find the rest of hot water control valve vacuum line just on the other side of the firewall grommet. You had the engine bay side of the vacuum line in your hand. Have you looked up by the blower motor ?




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[Pinky 1352]

Try this test. When your motor is cold try rolling your dash temperature control all the way to the hot side. If your airflow returns to your normal vents you just need to repair the hot water valve vacuum line. The rest are Ok. Rolling your temp selector to hot closes off the vacuum to the hot water valve, and therefore the vacuum leak, and returns good vacuum supply to the rest of the system and control of your dash vents. Nothing invites trouble like a half-ass radio installation job.





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After a few cups of coffee, I *think* I may understand the diagram.
So, what I'd like to try to see if I can get ANY vacuum to under-dash connector.
I know that it's the black line, and I know which side of the connector is supposed to go to source.
If I use the connection to the main vacuum source in the engine compartment and use a new vacuum hose, I *should* be able to connect that new vacuum line.

I'm just not sure if I can simply pull off the original black line in the connector?
I gave it a small tug, and it certainly isn't coming off easily, and I don't want to break it somehow.
Would anyone know if it's safe to give it a bigger tug, or should I just tee into the line, as I already have an assortment of vacuum line connectors/tees?

The source of vacuum is the black tube on shorter, upper, side of the connectors. All of the connections on the longer side feel like they go to the back of the climate control behind the dials on the dash.

OR

my alternative is to try and somehow get to the black and white line connectors at their origination points into the dash.

THAT is impossible to reach from inside the car. Even with my small hands there's no way to reach the spot that seems like its behind the air inlet door (at least I'm guessing that's what that part is.

anyone know HOW the main vacuum line connects behind the grommet? It certainly doesn't go all the way through it as it comes right out of the grommet in the engine bay. It doesn't look broken off, it looks like a clean cut.
So, I'm wondering of there's some other kind of connector on the inner car side of things, and if I pull out the grommet if I can reach this all from the firewall side?

Because if not, them I may be looking at a complete dashboard pull, which I can't do myself.

The second pic shows where the B&W vacuum lines are located, looking through the glove box. There's no way to get in there.

 

[Pinky 1352]

You'll find the rest of hot water control valve vacuum line just on the other side of the firewall grommet. You had the engine bay side of the vacuum line in your hand. Have you looked up by the blower motor ?




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Unfortunately, without taking the dash apart there's no way to see IN to the space by the blower motor and my hand doesn't fit in there enough to even feel for it.

I never did find a second vacuum line spot for the hot water control in the engine bay either. It does t appear that it went thru the firewall where the heater hose goes thru.

SO I'm still clueless as to how it's connection is supposed to get to under the dash.
A second vacuum line wouldn't have FIT in the opening of the grommet where the main vacuum line goes in. That line is a tiny diameter as is the center hole in the grommet.

I don't know if the main vacuum line has been broken at the firewall grommet since I bought it (that's the grey line that has a screw capping off the end) or if the latest mechanic managed to break it off when he replaced the front expansion valve in the AC and wasn't careful enough when he removed the battery and computer module.,

If that grommet does NOT have some kind of hard tee connection on the cabin side where the engine bay side can simply act as a junction, it means that I have to somehow run a new vacuum line.

Hence my idea above of just tapping into the molex type connectors for vacuum control that are near the floor on driver's side.

I'm just afraid to try and yank the black hose out of the connector there only to end up breaking something

 

[Hamfisted]

If the supply line isn't connected to a vacuum line there by the battery this is what the connection should look like....







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[Pinky 1352]

I managed to get vent selection control back.
Rather than risk breaking a port on the molex connectors themselves, I simply cut into the main vacuum feed black hose going to the back of the selector switches.
I ran a brand new vacuum hose from engine bay and fished it through to the cabin using the same thru-space that previous owner used to feed the power wire for the amp they put in.

I guess the crappy radio install job was good for something.

I'm still not getting cold AC (and the problem isn't the hot water control because it's set forward to the no flow position) but at this point I'm going to guess that the blend door actuator that I heard clicking earlier got stuck in the non-AC position or that something is still wrong with the AC system itself.



The odd thing is I'm no longer getting any clicking noise in the dash, and haven't for a while now.

I'm SO confused!

 

[Pinky 1352]

I figured I'd post an update.

It got to the point where nothing could be reached in and around the dashboard.
Trying to follow YouTube videos to change the blend door actuator proved fruitless, as there's was not enough room to remove it due to the metal frame that runs the length of the dash.

So I bit the bullet and ended up having a neighbor mechanic do the work of dismantling the whole dash.

While we were in there I got the heater core and AC core replaced, that actuator, and I ran some new vacuum connections. Hopefully the dash will never have to be removed ever again!

It turns out that Hamfisted was correct and on my firewall both the heat control AND main vacuum source went through that single grommet in the firewall.

BOTH vacuum lines were broken off on the engine bay side (and only the grey one was even still attached to the grommet at all!).
It was impossible to SEE that two lines should've been running through there until the battery and computer were removed and out of the way.

Anyway, new parts all around are in and neighbor is working on reassembling the whole dash.

Just in time as I think we're going to hit 110+ degrees next week!

Thanks everyone for all of the help!!!

 

[kep5niner]

The supply line comes in through the grommet in the firewall behind the blower. In the engine compartment you will find it down below the PCM. Or follow the hot water valve vacuum line back to the firewall, it shares the pass-through grommet. On the Expies with automatic climate control the control solenoid is under the dash right in front of the center console and you have to remove the center console to access it. I'm not sure the manual head unit versions even use this control solenoid but if you have it, that's where it is.


The vacuum line with the shroud over it is the hot water valve line. The bare vacuum line is the system supply line. This grommet is on the firewall just below the PCM unit....

View attachment 73610



This is the system vacuum control solenoid on the Auto systems located just in front of the center console under the dash ....

View attachment 73611







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Anybody know where I can get a replacement solenoid? The usual sites are all saying no dice. I understand the PN I’m searching for is 2L1Z-19D611-AA, according to the dealership. This is for my 2003 Eddie Bauer with the DATC. Entering that PN into ford.oempartsonline.com tells me it’s for the Navigator, not the Expy.

 

[Hamfisted]

Anybody know where I can get a replacement solenoid? The usual sites are all saying no dice. I understand the PN I’m searching for is 2L1Z-19D611-AA, according to the dealership. This is for my 2003 Eddie Bauer with the DATC. Entering that PN into ford.oempartsonline.com tells me it’s for the Navigator, not the Expy.

Kep that's the control solenoid out of my '03 EB with EATC ( electronic control head unit ...). I don't know why they would say it was only for the Navigator. Best thing to do is pull yours out and look at it and check the p/n on it. But it should be the same.

EATC control solenoid for Gen2 Expy





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[kep5niner]

Roger appreciate the follow up. Now I just have to find a place that has one. Already ordered from Ford Parts Giant, only to get the email “sorry, we don’t actually have it.”

 

[whtbronco]

I have gotten that email from FPG and Tasca several times. A bit frustrating to say the least.

Here's one on eBay:

Pardon Our Interruption...

 

[kep5niner]

I have gotten that email from FPG and Tasca several times. A bit frustrating to say the least.

Here's one on eBay:

Pardon Our Interruption...

Got it and snatched it up. Thanks whtbronco! It’ll be here Sunday, probably get it installed Monday. I’ll let you people know how it goes.