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2002-2008 Ford Explorer - Heat and AC Blend Door Replacement Parts

  This is a product developed by the HeaterTreater Engineers for the common blend door failure problem on 02-08 Explorers (02 was a change over year for Ford and both the old and new design were used.  Check photo's to see if your 02 is the older system). 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 Ford Explorers.   Every Explorer in this range either has, or will have, this common failure.  The pictures show the hardware provided for the fix.  The repair is done under the driver’s side dash, above the transmission tunnel. 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 Explorer 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.  This is the catastrophic fail mode.  Long before total failure, the system will exhibit problems with temperature control.  The computer controlled system goes through a calibration cycle every ~20 times that the vehicle is started.  This is the source of the continuing stress on the door, and as the door begins to “bend” and crack, the computer will detect an out of spec condition and shut down the actuator motor until the next cal cycle.  Since the system incrementally learns the position of the door, it might “catch” the next time and heal itself.  However, it won’t get better over time.  Intermittent failure to control heat or AC generally indicates a blend door problem.

 While the symptoms are fairly conclusive for blend door failure, the only way to really check it out is to remove the blend door actuator motor and  check the connection to the blend door axle. You can access the actuator motor from the driver’s side foot well.  The enclosed picture shows the location of the motor.  The motor is difficult to get to on this model.  We have a video posted in the TECH section that shows the location of the motor and will give you an idea of the difficulty of removing the motor.  The video shows a method of pulling back the dash skin to open more area to access the motor.  The motor can be removed without pulling the dash back, but it is a confined area and you will need flex sockets and various extension lengths.  

The video shows an example where the center divider can be cut and half of the dash skin pulled back.  On some year models the dash panel is different and you have to loosen both the drivers and passenger sides to pull the dash back.  The dash is built in the Ford factory as a stand alone unit and installed in the car before the seats, doors, steering wheel, etc.  There are a couple of screws that are inserted from the engine side of the plenum box that cannot be accessed from the front.  These screws are duplicates of screws inserted from the passenger side of the dash panel and our suggestion is to cut the plastic rececticles for the front driven screws to remove them.  This is not a significant impact on the structural integrity of the dash since this function is duplicated with screws that can be accessed fairly easily.  

Once you get access. the motor can be removed by removing 3 screws that hold it in place.  Inspect carefully for cracks or breakage in the blend door connection where it protrudes from the heater box.  You may need a mirror, or my preferred method, use a digital camera to take blind pictures and look for problems sitting on the couch.

You can now check the function of the motor.  There is a discussion in the TECH section under MOTORS that will give you some techniques for checking the motor.  It is common for gears to strip in the motor on a Mountaineer. This is a result of the system design and you can get more information on the problem in the TECH section.  Sometimes the motor will break before the door and functionality can be restored by replacing the motor.  It will break again, but may last a couple of years or so.  The only real fix is to replace the door and relieve the stress on the motor.  The HeaterTreater replacement is designed to overcome the design flaw in the system and will provide a permanent fix.  

Another reported fail symptom is a “clicking” sound coming from behind the HVAC system. On this model, this is usually an indication of a stripped gear in the motor.  Again, replacing the motor is a temporary fix without a properly aligned blend door.  The late model Explorer/Mountaineer is a complex  system with significant flaws in the design and no provisions for simple access and repair.  The fix is not easy, but we can resolve the issues.

The HeaterTreaterTM Solution:

This kit replaces the plastic doors and axle with stainless steel components.  All work is done under the dash and no disassembly 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.  The Explorer HVAC hardware is fairly complex including a lever to activate a vacuum switch to divert coolant from flowing through the heater core.  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 side.  The picture shows the cut pattern.  The kit also includes an aluminum strip that will be affixed to the box to fully support the cut out section when you replace it.  Complete diagrams for the cutting pattern are provided.  It's a very simple process.  The broken plastic door is removed and replaced with the HeaterTreaterTM. 

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 one of the harder ones to install, not because of the complexity of the replacement, but the limited access to the heater box.  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. 

The fix is very simple if you happen to be a 95lb left-handed double-jointed contortionist.  Otherwise, you’ll need to keep small children out of earshot, a couple of bandaids for scrapes and scratches, and a tube of BenGay.  You can do it, but it is a little frustrating.  The repair itself is easier if you remove the dash, but it takes a lot more work and time.  We will provide instructions for dash panel removal on request.

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 Explorer.  All our products are designed by degreed professional engineers and manufactured to exacting specifications.  If for any reason the hardware ever fails it will be replaced at no cost. 

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Patent Pending