Air not blowing through the front vents

dent770 · #1 08-20-2007, 07:21 AM

Good morning, I have a 98 Windstar and just recently the air stopped flowing from the front vents and is now flowing through the defroster. Several recommendations recommended changing the Air control switches. I completed that this past Saturday and ths action did not correct the problem. In speaking witht the Ford parts manager at the local dealership, he recommended also changing the front blower motor. My question is, if the air is flowing through the defroster, wouldn't that indicate that the blower is working? Or, does the blower motor control the movement within the system that controls where the air is flowing? Now that I have changed the switches, what else can I do to correct the problem before taking it into the garage? Thanks in advance.

garync1 · #2 08-20-2007, 07:31 AM

Sound like you may have a vacuum line loose some where or a leak in one. If you check under the hood you should see two small line running into the fire wall from the intake plenum. On a 2001 on is red and the other is black not sure on your year. But they are on the same side of the AC and the only two I see and that area. So you could take a look at those first. Make sure they are connected good. No the blower should be fine. But on my 2001 should be the same as far as being control by engine vacuum to make the blend door move to front or defrost..Temp blend door is controlled by motor. So your problem should be vacuum related.. Hope this helps...

dent770 · #3 08-20-2007, 07:34 AM

I will check this evening. I appreciate your advice. Thanks.

dent770 · #4 08-20-2007, 08:26 AM

As my AF title indicates, I am a Newbie. Therefore, risking embarrassment, I need to ask. Will I be able to locate the Intake Plenum when looking at the Haynes maintenance manual for the 1998 Windstar? Thanks,

wiswind · #5 08-20-2007, 06:32 PM

The "intake Plenum" is also called "upper intake manifold".
It is on top of the engine, has the throttle body on it......
A number of vehicle functions are driven by the vaccum from the engine, so there are lots of vaccum lines that connect to the upper intake manifold.

The most common cause of the problem you are having is, as mentioned above, loss of the vaccum to the actuators that move the air deflection doors.
The default position, with no vaccum, is the defrost position.
There are many vaccum lines that connect to the upper intake manifold.
One of them goes to a small box, still in the engine compartment, mounted on the passenger side inner fender near the top of the strut......near the passenger compartment.
This box holds a vaccum supply to hold the air door in position for when the engine is turned off.
From this box, another vaccum line passes through the firewall into the passenger compartment.
Inside the passenger compartment, if you work your head down and look up under the dashboard, you will be able to see the silver bulbs with stiff vaccum lines going to them. From each of these silver bulbs is a metal shaft that goes to a deflector door.

1 leak in the vaccum lines to the air control doors, and you loose the vaccum to the entire system, and the air will stay in the defrost mode regardless of what you select.

None of these are the " Blend Door" that is driven by a electric motor, and controls the temperature.

dent770 · #6 08-21-2007, 08:19 AM

Thanks for the clarification. Due to the weather, I did not get a chance to look for the hoses. With that said, driving into work this morning, the air started moving through the front vents. Since I did not need AC this morning, I shifted the knob to vent and air started coming through the vents again. Very strange. My guess is that the door is sticking.

Now what? Any suggestions? Thanks.

garync1 · #7 08-21-2007, 08:26 AM

Quote:

Originally Posted by dent770

Thanks for the clarification. Due to the weather, I did not get a chance to look for the hoses. With that said, driving into work this morning, the air started moving through the front vents. Since I did not need AC this morning, I shifted the knob to vent and air started coming through the vents again. Very strange. My guess is that the door is sticking.

Now what? Any suggestions? Thanks.

Well that could be good news,could have had trash or something in the air vent system that caused it to stick . I will check on my 2001 if there is a place to lube at least part of the linkage..BRB

Ok On my 2001 should be about the same. Under the glove box area,,Which thats a good thing because all you have to do is go on the passenger side and look under the glove box area you will see a vacuum diaphram with a metal bar looking rod that controls the vent airflow from what I can tell by changing over to AC vent controls it moved. There is on mine a orange hose that plugs into it. So you could look around that area and see what you find along with other vac lines as above posted..hope some of this helps. If you see cracking in lines or other signs could point to something. Also if you do find these signs a little bit of tape over the area could allow enough vac to test for a better result but thats just a band-aid to check for any change in results and should be repaired or replace if needed.

thesmith7 · #8 10-22-2007, 01:29 PM

Can any of you tell me if this is the same in a 96? Every setting but vent works on mine. I am guessing if I pull out the Glove Box and look behind I will find a vacuum line leaking. Is that a correct assumption.

Thanks

garync1 · #9 10-22-2007, 01:41 PM

Quote:

Originally Posted by thesmith7

Can any of you tell me if this is the same in a 96? Every setting but vent works on mine. I am guessing if I pull out the Glove Box and look behind I will find a vacuum line leaking. Is that a correct assumption.

Thanks

Does it blow air at all when on vent..???

thesmith7 · #10 10-22-2007, 02:18 PM

Quote:

Originally Posted by garync1

Does it blow air at all when on vent..???

Yes, I can hear it blowing no air comes through the vent though. It is like it is plugged or something.

garync1 · #11 10-22-2007, 06:49 PM

So from your first post I assume air blows out where its suppose to on every setting except vent. And on vent it must be blowing out somewhere else.?? If that were the case I think it may be a vac hose but I think on some of the year models like you have the door sometimes starts to break. I think Wiswind may have more info on this. If he does not add on you can Private Message him. He is good on getting back to you.. But he may pick up on this thread.. I would think it could be a vac or switch problem. I am a little lost on this one..I would think in AC mode it pulls air from inside van and on vent and heat the would be pulled from the outside.So Im sure the problem is in that area but vac or selector switch issue I am not sure..

thesmith7 · #12 10-23-2007, 10:39 AM

Thanks...I can't quite figure it out either. I think i'll do as you suggest and PM Wiswind and see if he can add any hints. Thanks!

wiswind · #13 10-24-2007, 08:23 PM

I have not had a problem with this on my '96 (shhh....don't want my old girl to get any ideas), so I am not experienced with this.
I did notice from looking up under the dashboard, there are several of those silver "bulbs" that are vaccum actuators for air direction control.
Is is possible that something went wrong for one of them?....
First step would be a look up under the dash to see if a vaccum line came off......
If you have a bad back.....this can be a challenge!

POST REPLY TO THIS THREAD