On Feb 27, 4:07 pm, "cw" > wrote:
> Followed Steve's advice, replaced blend door actuator, fixed problem.
> (http://groups.google.com/group/rec.a...plorer/browse_...
> )
>
> Here is my report:
>
> The situation
>
> 1997 Explorer Limited, AWD. Air conditioner failed with a clicking
> noise. Blew hot, then cold. Noise sounds like somebody tapping a
> hammer behind dashboard.
>
> Good mechanic at neighborhood gas station said he would have to remove
> dashboard, big labor job, $1200. Too bad, he said because the part is
> cheap. Has seen this a lot of Ford cars and Explorers. No way around
> it.
>
> Then I found the thread cited above. Opened glove box, pushed sides
> together so it would swing all the way down, revealing blend door
> actuator. See bundle of wires going into white actuator box. Unclip
> the wire bundle to stop the clicking. We are going to remove this
> actuator and replace it. Yes, they said it can;t be done without
> removing the dashboard. But they were wrong.
>
> Before proceeding
>
> Make sure you have or had clicking sound when operating Heat/cooling
> system. The clicking sound means only the actuator is broken. The
> actuator is a four-inch square plastic mechanism containing plastic
> gears. It's job is to mechanically move a "blend door" to achieve the
> cabin temperature you have selected.
>
> The blend door is just a flap, or door, inside the system that splits
> air flow to the cabin vents. If you choose max air, it closes off
> outside air and you get 100 percent AC. If you choose 70 degrees, and
> it is zero degrees outside, the blend door directs most of the heater
> output to you, allowing in a little outside air to keep it at 70. If
> you choose a cabin temp of 80, it lets in less outside air. In other
> words, the blend door "blends" the air.
>
> There is a shaft, or plenum, between the blend door and the actuator
> on top. If that shaft is broken, Google this: Ford Explorer Blend Door
> Fix by Jeff Frank. If you didn;t hear clicking, maybe that;s the
> problem.
>
> But if you have a clicking noise, the plenum is probably OK, and just
> the actuator is bad.
>
> Removing the actuator
>
> Start with several hours and a good mood. You'll need both. You may
> get discouraged. Hey, if I did it, you can. And you are going to save
> $1400.
>
> The actuator is white. Held in place by three 5/16th nut-screws (I.e.,
> screw with a nut head). The two in the front you can see. Feel behind
> the actuator, in the middle and slightly down, for the third screw.
>
> Not much room for your hand. You cant see much. This will be done by
> feel. After a while you will develop a mental picture of surprising
> clarity of this accursed actuator box.
>
> Because there is no room to work in there, you need the smallest
> ratchet wrench available. I had a 1/8-inch drive ratchet handle with
> 5/16 socket. Also have on hand a 5/16 spanner (simple double-ended
> tiny wrench).
>
> Remove the two front screws. It's not too hard.
>
> The third screw is the tough one. Before starting, duct-tape a piece
> of string to your socket. Tape another piece of string to the ratchet
> wrench handle. Also put a strong on the spanner. Now when you drop
> them back there, you can fish them out.
>
> The socket wrench will not fit easily on the third screw because there
> is no vertical room. You must get fingers in there with both hands,
> elevate the wrench horizontal, fit the socket on the head, and try to
> turn it. All at the same time. You will only have room to move the
> handle one "click" of the ratchet. This turns the screw about 1/8
> revolution. All this is at fingertip length. It seems impossible.
> Don't give up.
>
> When discouraged, simply feel again the work area. Study with a
> flashlight and a dental mirror. Get to know that area. At first,
> success will be stinkin' click of the ratchet! It took me two hours to
> get that screw off. Yes, its an uncomfortable position. Rest your head
> on the dashboard, and learn to see the world through the ends of your
> fingers. This is the $1400-dollar screw.
>
> Success!
>
> Now just lift or gently pry up the actuator and out it comes. You'll
> seen the plastic shaft that operates the blend door. It sticks down,
> which is why you have to lift the actuator before you pull it out.
>
> Open the actuator body (you can break the tabs) and you'll see several
> nylon gears and bushings. Take them apart and look carefully. If you
> find some gears stripped, you know why it was clicking. Only two tiny
> gears on mine were stripped, on the smallest cog-wheel. You want to
> find stripped gears, because that proves the actuator is bad (and
> that's what caused the clicking sound as the gears meshed wrong).
>
> The actuator has a number written on it. Mine said: F57H-19E694-BA.
> EATC (meaning electronic, not manual heater control.) This, I found
> out, is the "Service Number," not the part number. My part number
> turned out to be F77Z-19E616-BA.
>
> Call a ford dealer (or internet supply house) and order a new actuator
> ($83.26 as of Feb, 2007) . My ford dealer's computer showed the part
> in stock 20 miles away, so I drove and picked it up. I was also told
> that is part will be discontinued fairly soon. (If so, you can still
> find it on the internet, or at worst from a junkyard).
>
> Take the old actuator with you so you can make sure the new one looks
> exactly the same and says EATC. The new part number will probably be
> slightly different, but I was told this is "always the case." Still, I
> would insist on an explanation, since you must have the right part for
> your model year.
>
> Since you are now far, far too familiar with uninstalling the
> actuator, reinstalling it is simple.
>
> Just FORGET THE THIRD SCREW. You can't put it back anyway, probably.
>
> At first, I could not get the D-shaped nylon plenum shaft (sticks out
> the bottom of the actuator) to fit into its female hole. The shaft
> must be aligned just the way the D-shaped plenum hole is, or they
> won't insert. Scope out the current position of the hole with your
> dental mirror and try to get them the same.
>
> Don't try to rotate your new actuator shaft by hand, or with a tool.
> To rotate it, just hook up the wires, turn on the car, and operate
> your temperature control, which turns the shaft. Match the positions
> so the actuator shaft will fit into the plenum hole.
>
> What I eventually wound up doing was to hold the actuator in place,
> and keep changing the temperature setting up and down until they two
> shafts momentarily hit the point of alignment and slipped together.
> You'll know when it happens, the actuator snugs down nicely.
>
> The two front screws are pretty easy to reinstall. Dont overtighten,
> they are just bedded in plastic.
>
> That's all there is to it. Congratulations! If I can answer a
> question, you can contact me throughwww.shga.com. Go to the forum
> there, join it, and send me a private message. Note that I don't know
> zip about cars, but I do (now) know about replacing a Ford Explorer
> blend door actuator.
>
> Regards,
> Christian

Here is a good link with pics:
http://www.blenddoorfix.netfirms.com/