I posted previously about the heater fan working intermittingly. THAT WAS NOT THE CASE, THE FAN IS FINE!
After some investigation I find out that the fan is working fine, but where the air is being directed changes on its own! I will have it set for dash vents, then all of sudden it switches to the defroster or floor vents...

It used to be that where the air was being directed were controlled by doors or flaps that would open and close and direct the air to wherever the control was set. Are these doors or flaps controlled by vacuum or electrically? and on a 03 Escape does anyone know where to start looking for these controls?

I would hate to have the service guys at my dealership start pulling the dash apart to fix this, the dash would never be the same after that. I would have more squeaks and whistles than you can shake a stick at.

Remember this, anytime you have the dash pulled apart for a repair, it never goes back the same, even when a pro mechanic does it, believe me, been there and seen it many times..

 

Not sure about the Escape, but it is still a FORD. Most everything is vacuum. On my ford truck there is a vacuum check device between the engine and the firewall that is kind of cone shaped [about the size of a thimble]. Failsafe for the blower is to defrost in case the unit screws up you can still defrost the windshield, so when the check goes bad you get defrost regardless of what you select. Also goes to defrost on acceleration. I picked one up at a local auto parts for a couple of bucks. Worth a shot....

 

You described my situation exactly. Sounds like this check valve is failing and working intermittingly. If I have the selector set for dash vents air will sometimes blow out of the defroster then back again to the dash vents. I have also noticed that when the selector set for floor vents only, I still get some air blowing from the defroster.

Now to find this thimble sized coned shaped vacuum check on an 03 Escape with the 3.0 6cylinder engine. I just glanced under the hood today, but could not find anything like you described. I am going to have to take more time and really look hard.

Since the internet has just about all the information anyone would want, there must be a web site that can pin point this for me exactly. Thanks for you input, at least I have a starting point.

 

Looked under my 01 with 4 cyl today. It was right behind the engine along the firewall just under the windshield about center of the engine compartment. The one on mine is black and white and is smaller than the one on my truck was. Easy to spot on the 4 cyl, but will probably be harder to find on the 6. Good luck...

 

Here's a diagnosis that someone else got which is what everyone else has said so far:

Climate control going into default mode. Vacuum leak. Verified concern. Air distribution going into default mode upon acceleration or high engine demand. Inspected vaccuum source and reservoir. Okay. Performed vacuum leak tests with vacuum gauge and smoke machine. Located vacuum loss at junction block on left side of plenum. Not fully plugged in. Fully seat vacuum junction and retest. Okay

 

Thanks bananaboat, now all I have to do is find the "plenum?". I am usually pretty good with this stuff, but never had a problem of this kind before and don't know much about the heating and A/C stuff. So with that, where would the this plenum be located on the Escape? A plenum is where the air is distributed from the blower, I think anyway. I am thinking it may be under the dash near the blower motor on the passenger side. Any help?

By the way, the symptoms you described is exactly what is happening with my vehicle. On accelerating (negative vacuum condition) air defaults to defroster vents on windshield, when de-accelerating ( vacuum returns to normal) air goes back to where it was set on selector gauge.

 

The plenum is where the theoritical cabin filter resides that Ford doesn't install. Pop the hood, passenger side firewall, remove the black plastic cover below the windshield. It's held with some of those funky looking screws that pop in and out.

If you don't have a filter, Walmart carries the Fram carbon activated filter for about $6. I believe it's a CA-4303. Ford wants $20+.

 

The above must be for a vehicle other than an Escape. I found the so called "plenum" and could not find a "junction block on left side of plenum". So now back to square one trying to locate where the vacuum leak is.

I did find the location where I should put that "cabin" filter that Ford does not use or install on the Escape. It looks like its purpose to keep small particles from getting into the blower and presumably into the driving area of the vehicle. What is there now is a plastic mesh type covering that keeps large pieces of debris out of the blower. I can see where a filter placed in that housing will surely clean up the air a bit.

Again there are no vacuum lines or junction block in this area of the vehicle. That is why bananaboats comments are for a different type of vehicle.

 

Update! I stopped and talked to this guy I know who works for a local dealership in the parts dept. We took out the check valve and tested it very simply by sucking on the end of it and it is working fine. The guy told me these hardly are a problem on the newer Fords say over the last 5 or 6 years, but were a problem with older Fords. He said it could be one of several problems. The vacuum reservoir could not be holding enough vacuum, but then again he said the problem would be more significant and show up more. Vacuum leak at one of the vacuum servo motors which controls the air flow direction. On acceleration the engine produces negative vacuum, there may be enough vacuum during normal driving to keep the servo motors working properly, but under conditions where the vacuum drops or is minimal the climate control goes into default mode which is the defrosters. We checked under the hood and made sure all vacuum lines were secure and we could not hear any vacuum leaks. The condition improved a little to where it is only happening now under extreme acceleration like going up a long hill. So somewhere there is a slight vacuum leak that may go undetected until it gets worse.
If its one of the servo motors he told me to forget about and live with it. Tearing apart the dash getting to the motors and the workings of the heater/AC is a big pain in the butt and the labor charge will kill you. He told to live with it unless it gets to a point where the air is changing direction more frequently or if it changes during normal driving.

 

I had one of those controls go out in a ford ranger. I believe the dealer wanted $700.00 to repair because the whole dash had to come out, along with the heater plenum and I think even the core. My solution was to cut into the plenum inside the glove box, remove the servo motor, and attach a lawn mower throttle cable to the flapper. My son still drives the truck, you pull the cable for heat and push the cable for cooling. Cost to me, big fat O. Oh yeah, the servo on the Ranger is ELECTRIC, but is controlled by VACUUM. Gotta love those engineer type guys.