A/C-Heat intake vent??? Anyone....Anyone....? | Ford Explorer Forums - Serious Explorations

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A/C-Heat intake vent??? Anyone....Anyone....?

doonze

Well-Known Member
Joined
May 16, 2009
Messages
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City, State
Fayetteville, Ar
Year, Model & Trim Level
'93 X Sport
93 Sport (not that I think year matters on this) anyone know where the "fresh air" intake is for the A/C and Heating system??? I was thinking it might be in the cowl area where the windshield wiper motors are, but I'm just guessing, short of tearing the dash apart I have been unable to find it yet....

Thanks!
 



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On just about every modern vehicle with a cowl vent, that is where the fresh air is drawn into the cabin.

Is there some reason you think it could be from somewhere else?
 






Yes and no, I've been trying to find it there, and so far have been unable to do so, I was thinking (hoping) maybe it was somewhere else, but I'm thinking more and more that it IS there. I just gotta find a way to verify before I tear everything apart, I'll be really pissed if I tore the entire dash apart only to find it was somewhere simple and easy to get to! LOL Just trying to save myself some trouble.

Or maybe someone knows a somewhat easy way to get to the intake and "blend door" parts of the system??? I can't find a diagram anywhere to save my life.... :(
 






You can see the vents through the cowl mesh from outside the vehicle to tell that they're there.

The plastic vent tubing is all behind the dash, which you can see when you pull off the front trim, or looking under the dash with a flashlight.

The blend door and that stuff is usually accessed by just removing the glove compartment.
 






I wonder why I can't see mine through my cowl, but I'll trust it's there. I'm trying to figure out how the system routed (I get hot (read as HOT) air from the vents pretty much all the time, unless it's on floor, then I get hot, and i mean HOT air on my feet. Trying to figure out why)

I've confirmed in the past that I'm not the only one who always get's air no matter what settings are used. So I'm thinking it a common problem, where some door isn't being closed anymore where it should be, so I was trying to get an idea of where everything is, since I don't get much play time with the truck anymore! LOL

Pretty much my only choice, even on not-so-hot days is run the A/C, because I get hotter then warm air from the system. If I run A/C, then I get cooler then warm air. And sometimes after a long time truly cool air....

Anyway, thanks for the heads up Anime, I'm going to try and work on it for a little bit today and see what I can come up with.
 












May seem OT, but read on..

Is it normal on these 1st Gen Explorers for the A/C light to stay on even with the Fan switch Off? I mean, on most vehicles when you turn the Fan Off, the A/C goes off as well. But on my '91 Explorer, when I turn the Fan off, the A/C light stays on, and I have to push the button to turn it off. I thought my Fan switch was not actually going to Off, since I was getting air from the vents all the time, even with the Fan off. But, reading Doonze's problem, I see it is the Blend door not closing and so I am getting Fresh air all the time makes it seem Fan is on.

So, why is the A/C light staying on when Fan is Off?
 






I've also noticed the A/C on thing. What's more.... I can tell you that if you push the button, and the vent is open, and you have air flow, it will be cold. So in effect it's like a A/C outside air instead of fan air movement. I have verified for myself in the past that if that button is orange.... your A/C compressor is indeed running. Irregardless of fan settings.....

I'm not sure why they have done this... Ford brain power had a reason I suppose.

On OT, can you "pull out" your glove box and see what the lever is doing on your rig..... and let me know, I'm interested.
 






Will try to look into that tomorrow and let you know.
 






ok, doonze, I looked into it.

On mine the vaccum actuator was doing absolutely nothing whatsoever. So, pulled the trim off the kick panel there and pulled the vacuum line off. Checked it and had no vacuum at all.

So, popped the hood and, over to the right side of the firewall, above the heater core, is a long tubular vacuum canister. Coming from this canister is a line that splits. One end goes down, I assumed, toward the actuator behind the glove box. The other side just ended a few inches down. So, I grabbed some vacuum line, hooked one end to that and the other end to the vacuum manifold on the rear left side of the intake manifold. Then, went in the cab and and turned the vent control to Max A/C, and low and behold lots of vacuum to the actuator. The actuator now pulls the blend door shut and seems to hold good. Haven't tried driving it, but I revved it up a bit and never seemed to loose vacuum.

Hope that helps. Any more questions shoot them at me and I will be glad to assist in any way I can.
 






The idea of the vent door is to allow in fresh/outside air with the fan on but heat or A/C off, since the assumption is that if you've got the fan on, but not the heat or A/C, the outside air must be the temperature you want.

If you want heat, obviously it changes the source of the air to the heater core.

If you want cool air, but no A/C, it pulls from the vent since it assumes you're pulling in cooler outside air (if it wasn't cool, you'd be using the A/C).


Just one of those little quirks of Ford's climate control systems. They didn't think to put a recirc/vent switch on this system, even though other vehicles had them decades earlier.



Good tip on the vacuum fix Malchi, that should help a lot of people out.
 






Malchi,
Thanks for checking that out, on mine I do have vacuum, just not enough, and the second the truck is turned off the "plunger" releases. I got me a big ol' leak somewhere.

I did check out the black vacuum canister the other day when I discovered I had a vacuum leak, and all my lines seem fine :(. At least to where they go into the firewall.

Also, you said you pulled the kick panel and found the vacuum line? Did it go down from there or up? Mine seems to go up, but from what I was reading it seems maybe yours went down?? Maybe mine is routed funny?

On a side not, I believe from past post that if you have the Heater core bypass module on your truck that it also gets vacuum from that black canister under the hood. You mean this right??

P1050552-1.jpg



I guess I'll just have to try to track down my vacuum leak, I know it has to be somewhere between that cannister and the lever behind the glove box. Just have to track it down!
 






Doonze,

I'm not sure what direction it goes from there. I will check tomorrow and let you know. I don't know for sure, but is it possible that you don't have enough vacuum at the canister to hold? I will also check mine tomorrow and let you know what happens when I turn the key off. I would hope it is designed to hold shut, but you know Ford.....

Do me a favor, follow the vacuum supply line for the canister and tell me where it gets it's vacuum. Like I said, mine was disconnected so I just removed a cap from the manifold and plugged it in. I'd like to know where yours gets its supply.

And I'm wondering what that canister is for. Is it to give the Vacuum a boost, kinda like a capacitor? Or, is it maybe supposed to help keep the vacuum steady when you are driving? IDK.
 






Ok, first of all. From the actuator, the vacuum line goes kinda around towards the side panel, then behind the actuator, and down into a wiring harness that goes thru the firewall. I tried tracing it from the engine compartment, but everything is so tight I couldn't see where it goes. Hope that helps.....

Also, my blend door stays closed at highway speeds, as well as after I shut the engine off. as a matter of fact, it was still closed this morning when I first went out there after having sat all night. So, it is holding a vacuum very well.
 












I'm gonna put this reply in both my threads about this, so you might see double post....

I "fixed" my vacuum issue today with the outside vent. I was spending a day on the vehicles and decided I had the time to mess around with the lines. I found my problem about 20 seconds into it. I had started following the vacuum line from that black cannister thingie in the above pics, and the first one I couldn't plainly see where it went ended up going down into the engine about 10 inches and then it was cut. The cut looked like it had gotten caught between something and smashed in two. I got a flashlight and tried to find the other end, but I never could.

So I started the truck and sure enough, there was a vacuum leak right there. It wasn't enough to affect idle or anything, but I could hear and feel it at the hose. I tried to find a screw to screw into the hose to seal it (my goto move LOL), but I didn't have anything small enough. And I used to have a ton of vacuum caps, but I haven't seen them in years. I thought duct tape was a little overkill so some black electrical tape did the trick.

So I hooked everything back up inside, behind the glovebox, and it pulled the plunger down with quite a lot of force. I then turned off the truck, and it held the vacuum, I couldn't pull the plunger up. (I still had it removed at this point, just hooked to vacuum) So fixed it seems.

A couple of interesting points. It holds vacuum fine OUT of the truck and just hooked to vacuum from behind the glove box. But once I install it in the truck, it seems to slowly loose the vacuum. Not too fast, but maybe 5-10 mins? It seemed to be something about the angle the hose sits at once installed. When I was installing it it would hold vacuum fine until I started trying to get it back in place. Then it would lose all vacuum over a couple of second while I was moving it into place, and the hose has a pretty sharp turn right where it hooks up to the plunger thing. So I think there is a small leak that acts up sometimes right where the hose hooks to the plunger.

However after a test drive, it still holds more then enough vacuum to keep the vent closed while moving. So I'm calling it fixed and resolved. I did verify it ONLY closes the vent on OFF and MAX A/C..... All other settings the vent is open. I would rather have 100% control, but my other choice is 100% closed, so I'll play it Fords way. Really the only time it would matter would be on Floor Heat. There is not way to turn off the vent and have Floor Heat. You can just turn it to MAX A/C if you want Heat from the vents without outside air cooling it down. (it doesn't turn on the A/C, it's just the same setting as Panel except with the outside vents closed)

Oh, one other thing. I did track down the other vacuum lines from that "black canister" under the hood. Most lead into the firewall, but it is in fact "powered" from the vacuum octopus on the side of the intake.
 






doonze
thanks for the info wish I would have found it before I fought er fixed my clod air blowing all the time from the out side air deal.

To add the A/C running when in defrost is so you do not get the hot steamy windows of a bathroom in the winter being dry warm air defrost better then wet moist air any day.

That little on off switch at the defrost settings is there to speed up the motor a bit besides turn on the A/C/

Also the off and Max A/C spots are the only ones that depress the button on the vacuumed switch that controls the recycled air or out side air. there is no way for any other setting to do that being all other settings have that button up and all moving parts of the controls are then clear of it so there is nothing to depress it to still have recycling air in the cabin.
I also have a 93 XLT but as far as I know from 91 to 94 they all used the very same controllers and set up. so in your post at the start your right there are only two settings that give the recycled air all the rest is out side air be it across the evaporator or the heater its still out side air . Also your right on the off and Max A/c as I found nothing deferent between them just like you.

How it should work
The vac tank is to hold vac at low vac times such as WOT when there is little to no vac to pull from. The line that runs the inside /outside air dash pot is controlled by the temp controls. The tank lets it still run on max A/C even at WOT. There is a vac switch with two vac lines the temp controller. it lets vac come threw when on off or max A/C but shuts it off under the other settings allowing out side air to flow threw the system..

What go’s wrong.
There is a small button on the temp controllers Vac switch that is depressed when the lever is moved to the off or Max A/C detents. It is a metal plate and a plastic slider thing. They do wear and if that happens it can fail to depress the vac switch plunger button because it has lost its tension on it.

How to fix it
If you remove the control panel you can easily slip a washer under the plastic part but on top of the metal one to tighten things up and doing so will now depress that vac switch button.

Just did this to fix my 93 from always having out side air blowing threw the system.

This fix worked for me it may for you also and it’s a cheap one with almost no cost if you already have a washer you can use other wise that is the only cost.
 






I got a question now?if i dont have ac should i have left the black canister in there anyways?
 



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I do not believe it matters in your case as it's mostly for the A/c system and the hot air intake for warm up so you may never notice any real world change with it or with out it.
 






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