blend door fix

1995-2003 Ford Windstar - Heat and AC Blend Door Replacement Parts

  This is a product developed by the HeaterTreater Engineers for the common blend door failure problem on the Ford Windstar.  Please check our feedback to get an idea of the product line integrity and customer reaction to our products. We are committed to customer satisfaction and successful repairs of blend door problems. 

The HeaterTreater replaces the plastic blend door with steel. Replacing the existing door with another plastic door is at best a stop-gap solution. The failure is a result of excessive forces in the operation of the blend door.  The HeaterTreater attacks the root cause of the failure by constructing hardware that is designed to meet the rigors of normal operation of the HVAC system, and last for the life of the automobile.  The kit includes detailed instructions and all hardware required to complete the fix, including dremel bits and metal tape to seal the cut.

This is a kit to do a complete repair on the blend door malfunction that is common to the Ford Windstar.   Every Windstar in this range either has, or will have, this common failure.  The pictures show the hardware provided for the fix.  The repair is done through the center console opening and the glove box opening.  The work to install the fix is relatively simple and can be accomplished by the average shade tree mechanic. The work could easily be done by any local independent garage. Product returns are accepted within three weeks for a full refund(minus shipping).

The standard fix for the blend door failure is to remove the heater box and replace the plastic door.  Removal of the box requires removing the dash panel, evacuating and disconnecting the AC compressor, draining and disconnecting the heater hoses. Fixing the door is relatively easy, but the labor(and cost) of getting to the door makes this a time consuming and expensive job. The HeaterTreater avoids the hard work by providing a kit that allows the repair to be done with superior components without having to disassemble the automobile. 1-2hrs work vs 8-14 hours of work, and no specialized mechanical skills or tools required.


The Problem:

-  The Windstar is built with a Blend Door to control the heater and AC function.  The blend door controls air flowing through AC evaporator and diverts it into the vent system or through the heater coil, or any combination in between.  The doors are controlled by a DC  motor. The issue with the design is that the system has to calibrate itself and find the end points of movement before the computer can understand the two closed positions and regulate the temperature.  The motor is geared to move the doors slowly and with a good amount of force. The door has to withstand the force of stopping the motor, and like bending a coat hanger back and forth, will eventually break. 

Do you have the problem?

The usual symptom is an inability to effectively control the temperature of the HVAC system. The door hangs on a horizontal axis and total breakage will allow the door to fall to the bottom of the box, blocking air from flowing through the heater core…no heat.  Continual or intermittent failure to control heat or AC generally indicates a blend door problem.

The Windstar has problems with blend door breakage and with the actuator motor.  The automobile is also susceptible to problems with the re-circulation door.  Here is a list of things to check in order to diagnose temperature control problems.  The list is a little long, so feel free to pick and choose.

-        BLEND DOOR

The most common symptom is no heat.  The door breaks and falls to the bottom of the box, blocking any air from flowing through the heater core.  It is not a perfect seal, so there will be a small amount of heat, and it will impact the AC efficiency since some small amount of air will leak into the heater core with AC on.  Repairing the door will restore heat and improve AC efficiency. 

If you fully open the glove box, you can see the actuator motor to the left of the opening.  It is white and held on with three 8mm screws.  To get a full view of the plenum box and actuator motor, it is best to remove the center console control panel.  The hard part is removing the radio.  There are two holes on each side of the radio module.  These holes accept a special tool from Ford that will disengage the clip mechanism and allow the radio to be removed.  It’s not hard to do if you have the tool and have done it before, but otherwise is frustrating.  The tool is just a “U” shaped wire that is inserted into the two holes and pushed together to disengage the clip.  You need two U’s.  The tool is available from any parts store, or make your own with a fairly heavy gauge wire(a coat hanger is too thin).  A good car thief can strip a radio out in seconds, so it’s not difficult and with a little practice, you could also become proficient.  You can always go down to any car radio installation place and they can pull it quickly and probably won’t charge anything if they think there is a chance of selling you something.


With the radio out, there are two screws at the top of the center bezel and two at the bottom that have to be removed.  On some models, the console between the seats may have to be unbolted and pulled back.  The panel will pull out and can be completely removed by disconnecting the different wiring connectors to the HVAC control module and the different lights and functions.  With the center console panel removed, you have fairly easy access to the actuator motor. 

Remove the screws holding the actuator motor module  in place and pull the motor back to remove it.  Watch for plastic bits that will indicate a broken axle.  With the motor removed, you can use a large screw driver to turn the axle, checking for smooth movement and a hard stop with about 90 degrees of movement between the full open and full closed positions of the door.  If there is a “spongy” feel at either extent of movement, this is a good indication that the door is in the process of breaking and needs to be replaced.

One more unique thing to look for on the Windstar.  Notice in the picture that there is a metal tube that connects to the AC evaporator core.  If you look closely, you can see a scrape mark where the door hits this tube.  This is a design flaw in the Windstar and the lines going to the evaporator core do not have enough clearance for the door to avoid scraping the line.  When you are checking the door, you may feel the door scraping against this line.  This is a confusion point for the computer system since it will detect an intermittent resistance in door movement and can incorrectly calibrate door movement.  When this happens, the extents of movement are set incorrectly and the system will drive the motor past the normal stop point, creating excessive force on the door and causing breakage.  Note that the HeaterTreater replacement door is notched to avoid this problem. 


You may also find that the motor is not working and appears to be dead.  This is a common mistake and leads to a lot of motors being replaced when this is not the real problem.  You can check operation of the motor independent of the computer control with a 9V snap connector battery.  Check the tech info on our web site for details. 

Another reported fail symptom is a “clicking” sound coming from behind the HVAC system. This occurs when the motor gears get out of alignment and are slipping against each other, making the noise. Sometimes you can make it stop by pushing down on the back of the motor and getting the gears to catch.  The failure usually occurs with a broken blend door that allows the motor to get out of alignment and twist slightly, causing the gears to disengage. The HeaterTreater will put the system back in alignment and correct this problem.


The re-circ door has two positions, block external vent forcing air to be pulled from the internal port, or block internal port forcing air to be pulled from the external vent.  When the door breaks, both the external vent and the internal port are open and air will flow into the external vent and out of the internal port…like having a window rolled down all the time. 

The internal port is visible under the passenger side dash in the far right side(see picture).  On the bottom visible grate, you can see the door move back and forth if it is operating properly.  Since the Windstar is a mini-van and you probably have access to kids, this is a good job for them.  With the engine running, have the youngest put his little finger into the grate and turn re-circ on and off.  If you hear a loud scream when it pinches his finger, the door is OK…….WAIT,WAIT, WAIT, sorry that was for my kids.  For yours, squeezing under the dash and watching the door through the grate will also work.  The door is vacuum controlled and you can also see the vacuum actuator move to control the door. 

When the door breaks, you can usually see the broken axle where the vacuum actuator connects to the re-circ door.  If the observation is inconclusive, the final test is the “foot test”.  Have your kid sit in the passenger seat(seatbelt on) and take off his right shoe and sock.  Take the Windstar up to highway speeds and have the passenger feel for air coming into the passenger compartment through the grate to the far right under the dash.  If he can feel air coming in, the re-circ door is leaking and this may be the cause of a cold passenger compartment on cold days.  We are developing a fix for this door and if you need to replace yours, pestering us through email will speed things up.


The HeaterTreaterTM Solution:

This kit replaces the plastic doors and axle with steel components.  All work is done under the dash and no removal of the dash or evacuation of the AC system is required.  Tools required are a screw driver, socket set, and a Dremel tool(if you don't already have one, this is a good excuse and the tool has many uses. The area under the dash is confined and you will need either a stubby Dremel tool(~6” long), or a flexible extension for a larger industrial rotary tool. Target has a new rotary cutter product from Durabuilt for ~$30 that includes a flexible extension, variable speed motor, and every grinding bit known to modern Chinese technology(except the one you really need which is included in the HeaterTreater kit). 

The repair will take 1-2hrs, and once you have experience you can do another car in about 45min.  No extensive mechanical skills are required.  The picture shows the metal replacement kit.  All functionality is duplicated in metal in the HeaterTreater kit and the system will maintain full functionality (only better with unbreakable components).  The plastic door is accessed by using the Dremel tool and bit to cut into the plastic heater housing from the front through the glove box and center console control panel(after removing it).  The picture shows the cut pattern.  It's a very simple process.  The broken plastic door is removed and replaced with the

The instructions are written with multiple pictures and dual level instructions.  You can read the bold print only for experienced mechanics or read the bold and standard for full "instructions for Dummies".  The instructions are almost insultingly simplistic for those who care to read the entire document without admitting that they did it.  The fix is not difficult and MUCH preferable to disassembly of the entire dash and engine cooling systems.   

We have designed fixes for multiple automobiles and this one is medium difficulty to install.  The hardest part is getting the radio out.  Ford obviously did not anticipate blend door failures as a wear out mechanism and did not engineer easy access to the system for replacement.  The factory fix requires complete disassembly of the dash and HVAC system, so this is a shortcut process that will save big bucks over taking the Windstar back to the dealer.

We provide support via email or phone if required. Our goal is to make sure that every installation is successful. To date we have achieved that goal and have no intention of letting up. This will solve the problems with the blend door and is over-engineered to outlast the Windstar.  All our products are designed by degreed professional engineers and manufactured to exacting specifications.    This listing is fairly detailed and complex.  If your eyes haven’t glazed over yet, there is more on our web site with additional pictures.  We have successfully developed blend door fixes for multiple automobiles and if for any reason the hardware ever fails it will be replaced at no cost.   Our solutions are tested for ease of installation and reliability and we WILL make sure that your repair is successful. 



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