The temperature adjustment seemed to stop working correctly on our '96 Explorer. Seemed to be blowing all cold for my wife, regardless of temp setting (engine was plenty warmed up).
I played with it later, heard a dull knock from the heater area behind the glovebox now it's all hot all the time. Not a bad thing for living in Northern Ohio, but when summer comes, sweat city.
I pulled down the glovebox door and see the electric blend door actuator, a white plastic housing on top of the black heater plenum. Can hear it vibrate when I move the temp control, indicating that something's moving somewhere.
I popped off the actuator (held on by 4 expanding locating pins). It's a bit larger than a deck of cards. Seemed to work fine - the square shaft moves nicely over 90 degrees when I turn the temp control fully each way. That's probably the distance the blend door moves between full hot and full cold air.
With a dental mirror, I looked down into where the square shaft fits and see that half of the square female socket where the blend door actuator shaft goes, is broken on the blend door. So at best, it kinda flops around when the actuator turns. At worst, it does nothing when the actuator turns.
Question - can I pull the blend door out somehow? The actuator motor (the white plastic box) sits in a plastic bracket atop the plenum. That bracket is held in place by 3 screws. If I take the plastic bracket off will it let me get to the blend door? If I can pull it out and also yank out the broken pieces, I may be able to fix it myself.
Alternative of course is to take it to Ford where they will no doubt want to just replace the whole plenum, actuator, etc. for mucho $$.
The only way to remove the blend air door is to remove the plenum (unfortunately, the only way to remove the plenum is remove the instrument panel). I have heard of some guys hacking some sort of repair without removing everything or replacing anything - perhaps one or two of them can help you out. I can't vouch for the quality of the repair nor it's longevity...... I can say that the next poor sucker that buys something with hacked repairs usually gets the surprise of his life and, of course, it's the tech or the shop that becomes the bandit and not the hack artist that started this whole sorry mess (sorry if I sound like I'm venting..... it's just that I had the opportunity to speak my mind).
The dealer will indeed want to change the whole plenum since this is the only way to get the blend air door. Additionally, nobody I know is willing to stake their reputation on a hack job that could very well come back and bite them. Every time I ever set out to save a customer a buck, it would cost ME 10 bucks to do it and all too often I wound up with a p*ssed customer, anyway.
Yeah a very common problem, mine is like that right now and it sucks but like you I live in a cold climate so not a big deal, in the summer I just use max AC and it works ok would be nice to have the blend though. If you do a search on Google under Ford explorer blend door I am sure you are going to find a few sites and like the previous poster said you can do it w/o taking out the whole assembly.
Update on our blend door problem ('96 Explorer, temperature control stopped working due to CHEAP busted blend door shaft socket):
I took off both the white actuator motor assembly atop the plenum, as well as removed the plastic bracket that held that motor assembly. The front two screws of the bracket were fine, but that one last one towards the front of the truck was a real b*tch to get off. I would recommend filing down the sharp plastic lump from the dashboard bulkhead above or you'll peel the back of your hand down to the bone. Bear in mind you can pop-off the white plastic actuator with a large screw driver at each of the 4 corners (the motor assembly is held to the bracket with these nifty expando-matic clips).
With those two parts off (motor and bracket), I was able to measure the diameter of the hole where the busted blend door shaft sits (used a slide caliper on the inside diameter). In my case, the blend door shaft socket broke cleanly across two diagonally opposed corners of the square female hole. So essentially, I have half a blend door shaft intact, the other half probably sitting at the bottom of the plenum.
We'll stop for a second and say that this particular plastic piece was poorly designed, likely without enough beef to keep it from cracking at the corners where there's a lot higher stress. What they should have done was to add a metal collar of some sort around the outside to keep the female shaft part from busting like an exploded banana.
Anyway, I measured the hole to be 5/8" across, with the intact portion of the blend door shaft taking up exactly half of that diameter. This means all I have to do is find a short stubby piece of 5/8" something-or-other, cut it in half partway down it's length, then across halfway. I did find something to use, and it wound up being a 2" by 5/8" stub shaft. 1" from one end I cut lengthwise, then at the midpoint I cut into the shaft 5/16" to remove that piece. To give you a better idea, that removed piece looked like a little quonset hut (basically a half cylinder).
OK, so I put the half part of the shaft into the busted blend door hole, making the half shaft line up with the half-hole. Result is that I can now easily turn the blend door whatever way I want - hot to cold, etc., by twisting my stubby shaft. It rotates about 45 degrees in all. It still flops around but at least I can go from one temp to the other. I have to dump the the glovebox forward to reach way back with my hand though, which is a hassle.
By the way, with the fan on full blast, the blend door tends to slam shut towards the hot side. You can twist it back towards cold against the resistance of the airflow pushing on it (think miniature wind loading). That explains why the thing probably busted. The electric actuator motor is a pretty torquey little bugger - I could not keep it from turning when I was testing it (to make sure there were no stripped gears inside). So I would bet that over the years of turning the temp from hot on full fan to cold, caused enough stress at the axis of the blend door rotation to cause the stupid square plastic shaft hole to split the length of the blend door shaft.
But so far so good - I can at least turn the thing, but in order to do so I have to empty the glovebox and pull in the glovebox stops so I can get my hand way back there to turn my jimmied blend door stub from hot to cold or something in between.
Here's what I did. Removed my new blend door stub shaft. Drilled a 3/16" hole just above where the half-cylinder was removed. Took a 4" long thin bolt. Hammered the head of it flat and drilled an 1/8" hole thru the flattened part. The other end of that long thin bolt goes thru the 3/16" hole in the stub shaft I made, using two nuts, one from each side, to tighten the long thin bolt to the top of the stub shaft, horizontally. Result is that the long thin bolt acts as a lever to turn the stub shaft in the hole where the busted blend door is. The thin bolt is perpendicular to the axis of the stub shaft I made. Very much like how a small sailboat rudder works (you have this long wooden shaft in the cockpit which you control. It attaches to the vertical rudder shaft which goes down into the H2O).
That 1/8" hole on the other end of the bolt, where I hammered it flat, is for a length of coat hanger wire, bent to fit thru the hole and not come out. A great example of what I mean is how your lawnmower throttle cable fits into the metal throttle lever right at the carburetor. It has kind of a zig-zag bend to keep it from coming out as long as it's oriented horizontally (or as they say here in Cleveland, "orientated harizonnelly").
I bent the rest of the coathanger such that I have a loop on the other end, and so that it will not be too terribly disturbed when I close the glove box. The wire is probably about 8" long in all. Trouble is, the whole assembly I made - wire, bolt, shaft, kinda still flops around. Cured that by jamming a chunk of foam between the top of my jimmied shaft stub and the bulkhead above, of the dashboard behind the passenger airbag.
It's cheap and sleazy, but it keeps my shaft in the hole (oh my, there's a straight line!), plus offers some resistance so that the blend door has a reasonable chance of kinda staying where I set it manually when I push my coathanger wire in and out to adjust. And by the way, for you naysayers out there, no hack project is really complete unless you use coathanger wire. And/or duct tape. And I actually did use duct tape. A very small piece. To hold my loose 8mm socket to the socket wrench so it would not drop off and fall behind the plenum while trying to remove the plastic bracket screws. So there.
End result is that I have to open the glovebox (but not dump it like before) to move my coathanger wire in and out in order to adjust the temperature. But it beats the hell out of my wife driving to work in freezing weather with no heat and rapidly condensing windows. It all seems to work just fine now. I don't think I'd do the temp adjust while moving (have the passenger do it, as they're closest to the glovebox). Or more likely, just set it to hot in winter (pulled out) or cold for A/C in summer (pushed in). Also found I could hook-up the end of that coathanger wire to the metal frame just above the glovebox, inside. This keeps the wire up and away from tangling with the glovebox.
I took the elec connector for the actuator motor and tucked it under a nearby vacuum hose to keep it from hanging down and preventing the glovebox door from closing.
This was definitely a hack job but it scored major cool points with my wife who thinks it's nothing short of pure genius. Because bottom line she can drive to work again without freezing to death up here in Cleveland. And it didn't cost me nuthin.
OH, and finally, what did I wind up using for that 5/8" stub shaft? I used to have a 1988 Audi 90. It came with a beefy 5/8" threaded polyethylene rod that you twist into one of the wheel bolt holes (any of the female threads on the brake rotor). You then use that plastic rod to guide the wheel back onto the hub while you put the other three wheel bolts in. Basically holds the wheel in place for you since the Audi uses wheel bolts, not wheel nuts. I hung onto the thing for years for no particular reason. Guess it pays to be a packrat. Interesting that a German piece of engineered plastic was used as a hack to fix a cheaply designed American piece of plastic. Oh well.
I could probably just as easily have used a 5/8" wooden dowel or something too. Guess I'll just have to buy a South Bend lathe and a Bridgeport mill for next time, so I can make my own from billet aluminum. That would still probably cost less than having a new plenum put in.
Anyway, I hope this helps others who may follow with similar plight.
Mike, I was grinning the entire time I read your report. Nice bit of backyard engineering there, worthy of Red Green, himself! My sons have had many similar fixes to their cars and you are correct that a supply of coathangers and duct tape is essential.
Should you want to replace that mechanism and return to a dial adjusted heat system, there is another more involved hack available that allows accessing that door assembly from under the hood. You can find details at:
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Fianlly, if you shop around, the "official" fix of replacing the entire heater plenum at a dealer can be had for under $500. Thanks for the update.
Thanks for the kind words. The skin is starting to scar-over my knuckes finally.
Thanks also for that tip in the Accumulator newsletter. I printed out that easier access fix. I'd like to try it if I can get a shop to do the refrigerant work for me.
Any idea where I can get a new blend door? Is that actually a separately available part?
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