2000 Windstar Air vents not working right

Hello people, it's me again. Today I turned the A/C on but I had a big surprise when the air started to come out from the rear vents on the dashboard (defroster mode), I was using the defroster yesterday when I got home and turned the engine off. The air gets cold so the system is working fine but no matter which option I select on the controls the air will always blow from the rear vents.

Could it be possible to have a vacuum problem somewhere?. I read this post and I was thinking that maybe the same hose mentioned on post number 4 could be the culprit. Any other ideas?.

Thanks in advance for any help...

Sorry I forgot to post the link:
http://www.automotiveforums.com/vbulletin/showthread.php?t=1037944

Here's an update, I took a look at the firewall and everything seems to be ok, there were no loose hoses, any idea about what's going on?.

Thanks in advance

Vacuum leak or the control switch. The one that goes from Max A/C to other vents. It is a vacuum operated switch .

Where is the control switch located at? is it the same as the knob on the dashboard?, any idea about how to diagnose a vacuum leak?.

I found some engine oil leaking between the aluminum engine block and the plastic intake manifold, also the van has a diesel like sound. Could this be a vacuum leak and cause this problem?.

Thanks for your help.

I'm not an expert in the vacuum area. In fact I'm having the same problem with mine and I am looking for help.

The Moderator wiswind has a lot of info and personal experience with these vans. If he's watching he might help.

Here's my 2 cents (or pesos :tongue:):

From the back side of the engine and plastic intake plenum (yeah, that's what it's called) There are several vacuum lines that operate several systems. I'm not sure how many.
You checked the ones you could find and they look ok.
You might have missed one. I might have missed one on my van too.

Are you hearing a louder "sucking" sound from the back of the engine, with the hood up, while the engine is running?

Where? That's the tough part. I'm going to try a google search later.

Let's go inside the van:
The control panel has the radio, The AC/ Heat switch, an empty tray and the Ash tray and a storage bin.

1.To fully remove the Ash tray you need to remove the Storage bin.
The ash tray has 4 bolts 7mm. Two in front, two under.

2.The radio needs to come out. You need a Ford tool. Really two, thick and strong, horseshoe shaped wires. Insert the tools into the two holes on the left and the right of the radio. Pull the wire tool outward, away from center and slide towards you. (my son grabbed and pulled from the tape deck door) Unplug the wires

3. There are 2 bolts at the top of the radio area 7mm. The rest of the cover is held in with pop clips. REMOVE the cover.

4. 4 bolts hold the A/C control in place.

5. The right side switch has a plug and what looks like a wire harness. Carefully unplug that. Those are not multi colored wires, those are vacuum tubes.

6. Start the engine. Give it a minute. With your finger cover all the tubes one at a time. You should feel vacuum on at least one of the tubes.

If you feel some vacuum, then the problem is the switch that the tubes plug into.

If you don't feel any suction then the problem in under the hood. That's where I'm stuck.

Here is a vacuum schematic attached for the AC switch showing the colors and what the lines activate on the heater duct plenum.

grog11... You are awesome. Thanks a ton!

So, olopezm if you have the center control panel torn apart, the black tube should have suction with the car running.

Turn on the fan to the second or third setting. Leave the red "power plug" attached to the A/C heat selector. Turn that one to MAX.

Feel for suction at the Black tube with the vacuum harness disconnected from the control switch.

IF you have suction in the passenger compartment, then it's the switch. IF there is no suction, then the problem is under the hood.

grog11 That¡s such a great information, I will give it a try ASAP because I had some issues with my transmission and since it's still under warranty it's at the mechanic right now, transmissions will be the only thing I'll pay for from now on, and for any other thing related to cars I'm willing to do my best effort, I really appreciate all the info you posted and will post back whenever I have any info.

eddiem68: Thanks for your help too, I will post back ASAP.

Best regards to both of you guys...

Mine was caused by a loose connection on the vacuum lines that control the air "deverto flap", don't know th proper name. Used a small clamp, works great now.

Mine was caused by a loose connection on the vacuum lines that control the air "deverto flap", don't know th proper name. Used a small clamp, works great now.

Hello and thanks, I have no idea about what's that, could you please be more specific and tell me where that thing is located at?. Thanks in advance...

Each one of the vacuum lines connects to a vacuum "motor". When vacuum is applied the motor is in one position, and without vacuum it is in the other position. The motor (actuator) is connected to a "door" in the air ducts that directs the flow of air to the desired vent ports.

There are individual actuator doors for the defrost vents, dash vents, and floor vents. There is also a door to block or permit the flow of fresh air into the vehicle.

The hoses connected to the switch will travel behind the dashboard to the required vacuum motor. If you can access the end of the hose as it connects to the motor, you should be able to disconnect it, place your finger over the end and feel the suction. The vacuum pressure and flow should both be "strong", keeping in mind the small inside diameter of the vacuum lines. Using this approach will help to determine if the motor is faulty, or if the vacuum lines/controls are not providing the proper air flow.

Also, whenever you have a vacuum leak, it will usually result in a rough running engine and/or power train codes. The excess air entering the intake causes a lean mixture, which the PCM detects. A very, very light leak (one that probably wouldn't cause any problem with the operation of the heating system) may not cause a CEL or detectable engine misfire, but still could be noticed using a scan tool, showing low short term fuel trim readings.

If you believe you have a vacuum leak, the easiest way to find it is to listen for the hissing sound. Since most of the vacuum lines are located behind the enigne, this task is more easily performed with the cowling removed. I have found several damaged vacuum lines using this technique.

Thanks for your help tomj76, I've found the culprit thanks to eddiem68. It is a red hose running from the back of the engine to a 'T' shaped fitting which runs to the firewall and somewhere else on the climate control box to the left of the cowl which I still need to find.