A/C only blows out the window dash vents

TF43

MEMBER
2010 FORD EXPLORER SPORT TRAC
4.0L
V6
2WD
AUTOMATIC
85,000 MILES

No matter which position you select. I open the glove box, and check some of the vacuum lines, and none seem to have any vacuum on them, even if switching the dial from one position to another. The top vent actuator has a red vacuum hose to it and checking for vacuum on that line. None is present.

What controls, or where is the main source of vacuum created to feed these vacuum hoses?
Or would it be the blend door actuator that appears to be electrical?

Is there any relation to the EGR valve and its vacuum source? When we bought it the two lines on the EGR were unplugged and it throws a P0106 code now. So, this may be unrelated and require a different question, but it appears I need a new MAP sensor which is attached to the EGR valve.

Anyway, my question is to locate the main source of what controls the vacuum vent doors, so it'll blow out the proper vent when selected on the dial.
thank you gang, you've always have been most helpful.
Terry

7 Replies

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Hi,

The idea that you can't change airflow directions is likely related to the mode door actuator. It is controlled by the engine vacuum which is provided via a vacuum hose between the engine to the vacuum reservoir under the right side of the dash and then through the controller. There are three different actuators, floor, defrost, and panel.

Since you can't change anything, I suspect it is a vacuum issue. It's unlikely that all three went bad at once.

Locate the reservoir and check for engine vacuum at the hoses with the engine running. If there is no engine vacuum, trace the hose to where it goes through the firewall to the engine.

Let me know what you find.

Joe

See pic below.

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Sunday, December 19th, 2021 AT 12:31 AM

TF43

MEMBER
99 POSTS

Hi Joe,

So far, I found broken vacuum lines under the hood going to the intake manifold, but one appears to be the black hose for the EGR valve. Goes along with the red hose on the EGR, plus the other black hose that routes to the A/C through the firewall. The lower gray hose looks okay under the hood. I wouldn't be able to check the dash area until Saturday when the wife cuts loose with it again, LOL.
In the meantime, do you know the part number for all those hoses, or the size of the hoses? I might as well change all of them while I'm at it and be done with that part of it anyway. Thanks so much for the support. Merry Christmas and Happy New Year.
Not sure I can purchase locally. I live on a tiny island in the South Pacific, but if Dorman has numbers that would be great. There is always eBay.
Thanks again,
Terry

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Monday, December 20th, 2021 AT 9:53 PM

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Hi Terry,

There won't be a part number for them simply because of what they are. They could be different sizes. For example, many are 1/8", 5/16" and so on. The best thing to do is take a piece of it with you to a parts store.

Now when you say there is a disconnected hose, try something. Plug it and see if the HVAC works correctly then. It could be causing enough of a leak that enough vacuum isn't available. As far as the one that goes through the firewall for the A/C, I'm not sure what it would go to in the vehicle. Chances are it is the supply for the system of it goes into the vehicle.

Let me know if I can help in any way.

Take care,

Joe

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Tuesday, December 21st, 2021 AT 1:28 PM

TF43

MEMBER
99 POSTS

Hi Joe,

Many thanks for the speedy response. I have to assume the hoses are going to the vacuum reservoir? Haven't gotten that far under the dash just yet. Short of dropping the glove box lid, but I don't see a reservoir under the hood in the engine compartment. I'll see if our two little parts stores have vacuum hose to sell. Napa used to but has changed hands since and they haven't been much of a Napa like stateside stores. We have Hawthorne Machinery, that if I recall is a Car Quest parts carrier, so they would be my best bet.
I'll let you know what I find once I chase down the reservoir and replacement hoses.
Thanks much.
Terry

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Tuesday, December 21st, 2021 AT 9:07 PM

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Hi,

The reservoir should be in the vehicle, under the right side of the dash. Also, I feel confident they will have the vacuum hose needed. It is a very common item.

Take care and let me know what you find.

Joe