A/C Blend Door
#1
07-31-2008, 08:07 AM
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A/C Blend Door
I'm looking for a little info if anyone help. I have a 2000 Ex. with a diesel and I've recently started having problems with my a/c. I took it to a local service center and they hooked up their machine, added a pound or two of freon and $100 later, I'm out the door with the same problem. The rear air works fantastic but when I turn the air temp. **** for the front, it goes to hot and then back to ambient air temp. Not really cold. Now, I've searched all over this site for a "Blend Door Fix" and all I come up with are people talking about it but no one explaining what to do about it. Is this just an "urban legend" or myth and I'll still have to replace the whole contraption, or is there really some kind of fix? I haven't looked yet to see if the door aperatus is actually moving or not but I'm pretty sure this is where my problem is. If someone could post a link to this fix I sure would appreciate it.
Also, concerning my slow moving windows, is it true that all I need to do is apply some lube to the inside felt track to help eliminate this problem? I have a real good synthetic, clear lube that works great on many other problems. I'm curious if this should do the trick or do I need to take the door panel apart and lube some gears and tracks that are not visible to the"assembled" door. Any input here would be great as well. Thanks in advance.
Beau
Also, concerning my slow moving windows, is it true that all I need to do is apply some lube to the inside felt track to help eliminate this problem? I have a real good synthetic, clear lube that works great on many other problems. I'm curious if this should do the trick or do I need to take the door panel apart and lube some gears and tracks that are not visible to the"assembled" door. Any input here would be great as well. Thanks in advance.
Beau
#2
07-31-2008, 02:26 PM
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I'm almost in the same boat with you on the AC. Mine is in a default mode were it only blows out the defrost holes. However mine is still cold. I have been told that it was a vacuum leak somewhere. I haven't had the time to get into it and figure it all out. I dont know about the door situation. So as of right now I have the windows down and air flowing from outside. As for the onther issue about the windows being slow. I would just use what you have and see if that works. I too agree all the talk about the problems but nowhere to look for the fix. Sorry.
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07-31-2008, 02:59 PM
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I've had the same problem for a few years now. I posted the following thread when it first started. The last poster sent me a pm after a while, where he had replaced or lubed an electric motor and cured his problem. I've never tried to get back there yet to look at it. Mine does switch over, but sometimes it takes awhile, and I have suspected a vaccum problem. The last time it happened, I was pulling my boat on a hilly, winding road and the A/C was stuck on defrost. I turned the switch to defrost (so as not to fight it) until I came to a stop sign, where I tried to switch it back to A/C and it worked. The vaccum theory makes sense as there would be more vaccum available at idle. It might have just been dumb luck though. My guess is that it probably is electric and not vaccum operated.
https://www.ford-trucks.com/forums/3...-the-heat.html
https://www.ford-trucks.com/forums/3...-the-heat.html
#4
07-31-2008, 05:44 PM
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#5
07-31-2008, 09:28 PM
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Hey guys, thanks for the replies. After further investigation, I'm not so sure about the blend door being the problem. I took the glove box door off and just a little left of center is a silver rod that's vertically attached to a door(damper) at the bottom and a vacuum pump up top. I assume this is the blend door and it does move up and down and adjusts the door when Function Selector **** is moved. When I move the temperature ****, I dont see anything move. I don't know if this is right or wrong but it does get hot when I turn the **** into the red but it only gets midly cold when I turn it back to blue.
I have a spare temp. selector switch from a spare overhead controller. Would it be a good idea to switch out the one in the dash for the spare? Maybe this way I can narrow down the problem. Any further ideas related to this new information would help greatly.
Tomorrow I'll try the lube in the felt track and report back the results. Thanks!
Beau
I have a spare temp. selector switch from a spare overhead controller. Would it be a good idea to switch out the one in the dash for the spare? Maybe this way I can narrow down the problem. Any further ideas related to this new information would help greatly.
Tomorrow I'll try the lube in the felt track and report back the results. Thanks!
Beau
#6
07-31-2008, 09:38 PM
I have had my blend door out of my Ex. and it is located under the glovebox area. If you squeeze the sides of the glove box to remove it and disassemble the ductwork the blend door is fairly easy to access. It turned out not to be my problem as I could see how it worked as the temp. **** turned. I did disassemble it to see how it worked. If I remember it has a motor that turns a gear to operate the door. It might be worth investigating. My problem was that the air would not change from the defrost to the dash vents. There is a vacuum actuated door that is about directly behind the radio or that strange hook thing. I removed that hook thing and had a difficult time working with one hand to replace this inexpensive vacuum diaphram. That fixed that problem.
I'm not sure if there are two separate lines in the AC. The rear has lines that run along the frame. Find the lines that enter the front box and feel if they are cold. If they are then check the blend door. Good Luck JOHN
I'm not sure if there are two separate lines in the AC. The rear has lines that run along the frame. Find the lines that enter the front box and feel if they are cold. If they are then check the blend door. Good Luck JOHN
#7
06-04-2012, 02:10 PM
Hey Beau,
There are three air flow control functions in the Excursion. 1) re-circ, 2) mode(defrost vs vent vs floor), 3) Blend door. The first two are vacuum controlled. A vacuum motor has a digital function. Vacuum--no Vacuum Open door--closed door. The blend door has to be able to regulate between the two extents of movement in order to "blend" the air and reach the right temperature.
The rod you are seeing is most likely the control for the re-circ function. This is easy to check. With re-circ off, you will feel an air flow into the external vent between the hood and windshield, and the flow will stop with re-circ on. A piece of kleenex is a good guage. The box has a vacuum motor that is on the side of the bo
left hand side through the glove box) that controls the re-circ door. The mode control is on the bottom of the box and the rod shouldn't be exposed. It bolts into the bottom left and the movement is contained within the box.
If you have a vacuum problem, it will show up as an inability to switch between the different modes, and failure on the "kleenex test". Unfortunately, a broken blend door is a common failure on this design and is actually a design flaw. I just wrote a long explanation of the cause of the problem and you can search my user name on this forum to find it.
Most likely you don't have a vacuum problem and the only way to be 100% sure of a blend door problem is to access the actuator motor on the bottom of the box. Most likely the motor sits just above the transmission tunnel. On the F150, it is accessed most easily from the driver's side and on the Expedition, you have to remove the center console and access the motor from the passenger side. On both models there is an air distribution duct on the bottom of the heater box that covers the actuator motor. This duct distributes heat to the passenger and driver floor boards. It is not a structural or high pressure vent and you may have to cut it in half to remove it. It can easily be patched with duct tape and replaced. A little leakage is not a problem. Check the pictures on the HeaterTreater Expedition Ebay listing for some pictures of what you will likely have to deal with.
Once you get to the motor, it is easy to remove the screws and pull the motor down. If it comes out with a handful of black plastic pieces, you have a broken blend door and it will have to be replaced. Once you have the motor off, you can manually switch between heat and AC by turning the axle with your hand. Check for solid opening and closing and temperature change. You can also observe movement of the motor and make sure that it is receiving signals and operating. If the axle is broken, the motor will have calibrated outside of spec range and the computer shuts the motor down to avoid damage or something. If the motor doesn't work, that doesn't necessarily mean that it is bad.
It will take a little creativity to get to the motor and check it out, but it's either that or big bucks to the dealer. I'd certainly be interested in what you find and even more if you can get a few pictures. Again, I don't have experience with the Excursion directly and the advice I'm giving is based on the F150 and Expedition.
cgallen
There are three air flow control functions in the Excursion. 1) re-circ, 2) mode(defrost vs vent vs floor), 3) Blend door. The first two are vacuum controlled. A vacuum motor has a digital function. Vacuum--no Vacuum Open door--closed door. The blend door has to be able to regulate between the two extents of movement in order to "blend" the air and reach the right temperature.
The rod you are seeing is most likely the control for the re-circ function. This is easy to check. With re-circ off, you will feel an air flow into the external vent between the hood and windshield, and the flow will stop with re-circ on. A piece of kleenex is a good guage. The box has a vacuum motor that is on the side of the bo
left hand side through the glove box) that controls the re-circ door. The mode control is on the bottom of the box and the rod shouldn't be exposed. It bolts into the bottom left and the movement is contained within the box.If you have a vacuum problem, it will show up as an inability to switch between the different modes, and failure on the "kleenex test". Unfortunately, a broken blend door is a common failure on this design and is actually a design flaw. I just wrote a long explanation of the cause of the problem and you can search my user name on this forum to find it.
Most likely you don't have a vacuum problem and the only way to be 100% sure of a blend door problem is to access the actuator motor on the bottom of the box. Most likely the motor sits just above the transmission tunnel. On the F150, it is accessed most easily from the driver's side and on the Expedition, you have to remove the center console and access the motor from the passenger side. On both models there is an air distribution duct on the bottom of the heater box that covers the actuator motor. This duct distributes heat to the passenger and driver floor boards. It is not a structural or high pressure vent and you may have to cut it in half to remove it. It can easily be patched with duct tape and replaced. A little leakage is not a problem. Check the pictures on the HeaterTreater Expedition Ebay listing for some pictures of what you will likely have to deal with.
Once you get to the motor, it is easy to remove the screws and pull the motor down. If it comes out with a handful of black plastic pieces, you have a broken blend door and it will have to be replaced. Once you have the motor off, you can manually switch between heat and AC by turning the axle with your hand. Check for solid opening and closing and temperature change. You can also observe movement of the motor and make sure that it is receiving signals and operating. If the axle is broken, the motor will have calibrated outside of spec range and the computer shuts the motor down to avoid damage or something. If the motor doesn't work, that doesn't necessarily mean that it is bad.
It will take a little creativity to get to the motor and check it out, but it's either that or big bucks to the dealer. I'd certainly be interested in what you find and even more if you can get a few pictures. Again, I don't have experience with the Excursion directly and the advice I'm giving is based on the F150 and Expedition.
cgallen
I have no air coming out of the front headliner vents. The front ac works great, the rear headliner vents work great as well.
I have the rear ac setting set to panel, AC is ON on the front. There is no air coming out of the 2 headliner vents behind the driver and passenger . Where is the valve that controls this ?
Also, where is the air supposed to come out of when I switch the rear button from panel to floor ? where is the floor opening ?
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#8
08-27-2012, 07:36 PM
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Hey just to let you know my f350 was only blowing cold out of the dash and it turned out it was the vacuum pump that also operates the 4wd located on the passengers side under the hood under the insulation cover. It has one vacume line going to it and a electric connector also and has four rubber shock cushions connecting it to the truck , very easy to fix ! under $100 bucks !
#9
09-21-2013, 08:39 PM
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turn signal wire colors
I am installing some 2008 mirrors on my f350 and everything is working but the signals . I wanted to know if anyone knows the colors of the wires for the turn signals ? I am hoping to splice in on the harness that runs to the back of the truck that goes behind the drivers side kick panel and under the rocker panel because it is very easy to access and that is were I found the brown wire for the marker lights . I figure two of them wires have to be the signals . I started checking them out with a test light but I don't want 40 wires with holes in em from me trying to find the correct wires . My truck is a 2002 f350 crew cab. I would appreciate any help , Thanks !! 
Last edited by mdayz28; 09-21-2013 at 08:41 PM. Reason: supposed to be a new post
Does anyone know why the rear a/c vents are colder at least 10 degrees than the front? Not fun in AZ 110 degrees!
#12
05-19-2017, 02:14 PM
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I am installing some 2008 mirrors on my f350 and everything is working but the signals . I wanted to know if anyone knows the colors of the wires for the turn signals ? I am hoping to splice in on the harness that runs to the back of the truck that goes behind the drivers side kick panel and under the rocker panel because it is very easy to access and that is were I found the brown wire for the marker lights . I figure two of them wires have to be the signals . I started checking them out with a test light but I don't want 40 wires with holes in em from me trying to find the correct wires . My truck is a 2002 f350 crew cab. I would appreciate any help , Thanks !!
#13
07-21-2017, 04:38 PM
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Are there any pictures of the front A/C air blend door repair? Reading the FSM it looks like a fairly straightforward procedure but would like some pictures before I dive in and start ripping apart things that don't need to be removed.
Also it wouldn't hurt for a sanity check on my diagnosis. Rear A/C works steadily. Front air diverters are all working. When I accelerate with the engine hot the front starts blowing heated air. When I brake it turns back to cool. My guess is that the blend door is broken/loose and flopping open and shut as I accelerate and brake. Sound plausible?
Also it wouldn't hurt for a sanity check on my diagnosis. Rear A/C works steadily. Front air diverters are all working. When I accelerate with the engine hot the front starts blowing heated air. When I brake it turns back to cool. My guess is that the blend door is broken/loose and flopping open and shut as I accelerate and brake. Sound plausible?
#14
07-23-2017, 01:56 PM
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It was the blend door. But actually replacing it looks like it may involve removal of the entire air flow system. It appears that the point where the shaft of the blend door motor connects is worn, allowing the door to just flop around. As an interim fix I just have it propped open.
It looks like the design allows some air to still flow past the heater core even with the door open. Plus the heater is still receiving water even with the system at "max" (60F). I will be testing the vacuum water valve next. If that does not completely shut off flow by design I am considering adding a manual cutoff or diverter.
There is a decent video of the process of getting to everything at <https://www.youtube.com/watch?v=2B3tj61QXuw>. Some additional info: Tools needed = 8mm socket, 8mm box end (preferably ratcheting), and a Phillips head screwdriver. Not shown on the video, probably because the Super Duty doesn't have it, is that you need to remove the bottom cover under the glove box. You don't really need to remove the glove box. It wasn't too much in the way. If you want to unplug the glove box light (I couldn't get the bulb out) the locking tab is on the top of the plug. If you are reading the FSM it doesn't show that back screw on the blend door motor. Twisting the blend door motor loose takes quite a bit of force. Give it a good hard yank when twisting. Last of all putting the heater core cover back on is a minor PITA. The video mentions lifting it over the tab but there is a module over it that doesn't allow it to go high enough. I had to slide it on from the side.
If you have an air compressor this is a good time to clean the air ducts and behind/under the dash. Surprisingly the dirt/dust wasn't that bad for the age but it still needed cleaning.
It looks like the design allows some air to still flow past the heater core even with the door open. Plus the heater is still receiving water even with the system at "max" (60F). I will be testing the vacuum water valve next. If that does not completely shut off flow by design I am considering adding a manual cutoff or diverter.
There is a decent video of the process of getting to everything at <https://www.youtube.com/watch?v=2B3tj61QXuw>. Some additional info: Tools needed = 8mm socket, 8mm box end (preferably ratcheting), and a Phillips head screwdriver. Not shown on the video, probably because the Super Duty doesn't have it, is that you need to remove the bottom cover under the glove box. You don't really need to remove the glove box. It wasn't too much in the way. If you want to unplug the glove box light (I couldn't get the bulb out) the locking tab is on the top of the plug. If you are reading the FSM it doesn't show that back screw on the blend door motor. Twisting the blend door motor loose takes quite a bit of force. Give it a good hard yank when twisting. Last of all putting the heater core cover back on is a minor PITA. The video mentions lifting it over the tab but there is a module over it that doesn't allow it to go high enough. I had to slide it on from the side.
If you have an air compressor this is a good time to clean the air ducts and behind/under the dash. Surprisingly the dirt/dust wasn't that bad for the age but it still needed cleaning.
#15
07-30-2017, 12:31 AM
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Update - well it wasn't the blend door after all. Well, actually there was a problem with it but it was not causing the AC/heat flip flow issue. It was that old standard problem - a small vacuum leak. There was enough vacuum to move all the flappers and _almost_ close the heater water valve. At idle water flow was low enough that the air was cold. When the engine speed increased the water flow past the valve was high enough to overcome the A/C. Getting the vacuum leak fixed resulted in having to redirect the air to where it was not blowing on me today as I was getting too cold. OAT was 101F.
A good lesson. I am always harassing my mechanic because he will find "a" problem but never test to see whether it is "the" problem. And here I am making the exact same mistake.
On the vacuum subject it at least for my vehicle it is a fairly common problem. Surprisingly the lines themselves are holding up very well. The problems I have run into are either a line being cut or pulled loose by accident or a leak at a fitting that just needed the line to be removed, everything cleaned, then reattached. As I mentioned in an earlier post the FSM has a REALLY good testing procedure. If you go through the whole thing it is several hours of work but it will find any problems. A Mityvac tool is worth its weight in gold and is pretty cheap. $20 - $40 depending on the model.
A good lesson. I am always harassing my mechanic because he will find "a" problem but never test to see whether it is "the" problem. And here I am making the exact same mistake.
On the vacuum subject it at least for my vehicle it is a fairly common problem. Surprisingly the lines themselves are holding up very well. The problems I have run into are either a line being cut or pulled loose by accident or a leak at a fitting that just needed the line to be removed, everything cleaned, then reattached. As I mentioned in an earlier post the FSM has a REALLY good testing procedure. If you go through the whole thing it is several hours of work but it will find any problems. A Mityvac tool is worth its weight in gold and is pretty cheap. $20 - $40 depending on the model.
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