Blend door air mixer photos

[jblc]

Does anyone have photos of the air mixer and blend door?

It's related to my attempts to tackle the cabin leakage issues i posted about eg here.

i've narrowed it down to what I think is the HVAC output -- vs leakage through gaps, or the rear air-escape vents.

But, in order to know how i might be able to modify it, i'm looking for photos. I have no idea what that module looks like, and can't find anything online either -- including parts suppliers.

Thanks

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[airline tech]

Borrowed pic from another thread, the air recirculation door is just above the cabin air filter, the very first thing I noticed when driving my truck, it does draw in an extreme amount of outside air.
Smells galore, skunk exhaust fumes etc,.

I have not tried keeping it closed (Re-Circulated) air as of yet, I did do some research on this door and confirmed it does relax open when powered off, thus allowing mice to enter cab of truck.
This is the only door for HVAC that allows fresh air in, if you are getting smoke in cab with door closed (Re-Circulated) then possibly door is not closing completely, however I don't think it will create an actual airtight seal.

If you remove some of the cowl push pins, just under the wiper blades and raise it up just a little. put flashlight shining towards the inner trough (inlet for the HVAC) you will see what I mean when it's pulled up

From inside cab, remove glovebox and cabin filter, with flashlight shining at the door, start truck and cycle your recert fan (switch) on sync screen, you can watch door open and close, check to see if closing fully or hanging slightly open.

Note: actual pic of door is borrowed from another poster's thread, you can see light shining at the door, this is the spot to look at.

It's possible that the door actuator needs replaced or recalibrated or mice have built nest there blocking door operation

Air Inlet Door - Just above Cabin Air Filter, this door closes when you select recirculated air and is the only door in HVAC that allows outside air in Cab

You will also have some air leakage around cab door seals, the only other is your rear exhaust venting behind rear seat, but the doors generally allow some airflow through them to vent for moisture due to water intake (windows)

 

[jblc]

This is great -- thanks for your informative post

"the air recirculation door is just above the cabin air filter"
"This is the only door for HVAC that allows fresh air in"

Ah, good to know, thanks.

"

I did do some research on this door and confirmed it does relax open when powered off"

Agreed, and it's unfortunate. Here's my approach to preventing that. And this is what i do to prevent mice from damaging if just in the engine compartment

"You will also have some air leakage around cab door seals, the only other is your rear exhaust venting behind rear seat"

Yep, but it's not leakage through door or window gaps, or the rear air-escape vents. I used a few methods to detect air exchange along there, and they're minimal.

"From inside cab, remove glovebox and cabin filter, with flashlight shining at the door, start truck and cycle your recert fan (switch) on sync screen, you can watch door open and close, check to see if closing fully or hanging slightly open."

Excellent. This might mean I can play around with it a bit (albeit with difficulty), without having to remove the dash.

Thanks again for taking the time to write this out.

 

[airline tech]

Yes, I already planned on the screen covering to inlet holes, it's a shame Ford has not addressed this issue, that appears to be quite common, and thanks to this forum I am informed of the issue.
I could only imagine driving along when a mouse comes crawling up my leg or runs across the dash, that would be an alarming event when you're not expecting it.

 

[Racket]

I suppose there's no way to 'program' the vent to remain closed when the truck is off. I'd sure like to keep the mice out.

 

[airline tech]

It is something I was planning on looking at, but when power is removed, door relaxes to 1/2 open, gravity drops open
It takes power being applied to pin 3 to close door and power to pin 7 to open door.
So, more power drain on battery with truck off
The reason for door opening with power off is to vent the Heater Box, (Musty Smells) from the AC Evaporator
So, if you search mice, you will see the screen add mod you can do to prevent mice from entering cab of truck, they access this area by the cowl drain ends (Left/Right), there is a small area on each end of the cowl (under wiper blades) where they can enter and access the inner cab framework (inlet) to the Cabin Air Filter
The screen mesh inlets (you see) in center of the black cowl are the air inlet for HVAC, which air flows back and down into the framework, I just wish Ford would at least put inlet screen on the inner frame to prevent mice, bugs, bees from entering while being built

 

[jblc]

Great, thanks for the pinout diagram.
Out of curiosity, where do you have your knowledge from...are you a mechanic?

It takes power being applied to pin 3 to close door and power to pin 7 to open door.

Hmmm, that's not how i read the schematic. The motor looks to be a standard brushed motor with two connections, so the + and - (perhaps gnd) voltages need to be present on both for it to hold the open or close position. Holding one polarity across both pins opens, and the opposite polarity closes. Power on one pin will do nothing, if the schematic is accurately drawn


From earlier post:

then possibly door is not closing completely, however I don't think it will create an actual airtight seal.

I read someone saying that the blend door is designed to always pull in 10% outside air.
The problem is that above 35-40 mph, if outside is smoky, fumes, etc, that 10% flow is more powerful than what the cabin filter can filter out -- effectively making the inside equivalent to outside air quality even at 100% power while recirculating.
I'm planning to see if I can add extra components to seal that 10% (or reduce it).

1) As a way to over-ride recirc constantly switching off, while driving: perhaps the pot feedback (pin 5) could be switched to a manually set constant voltage (based on a previously measured, known "open door" voltage), while the motor leads (pin 3/7) could be disconnected from the interface module and manually set to hold the door closed.
Since it seems to be an all-analog setup, perhaps even a basic switch could do this, eg 3P3T (depending on whether any power is needed to hold the door open, or if it's truly gravity assist only).

Does anyone know if there's any other feedback that would throw an error code for the blend door, if over-riding it this way? Eg another temp sensor monitoring the flow path.

2) One other solution I hope to try is to fool the humidity sensor per this post, so that recirculation is never shut off (this new recirc-always-on mode could be manually selectable).
Depending on the form out the module's output signal -- CAN? Analog? Some other bus? -- maybe that could be manually switched to a known output when desired, forcing recirc to Internal. Or, a modified humidity sensor whose output is modified (eg disconnect lead, inject <N> mV instead to indicate low humidity)

Does anyone know the humidity sensor part with certainty? My above linked post never resolved that.

 

[jblc]

One more:

3) Does anyone know why there are two actuators in the diagram here?
13 is "HVAC Air Adjustment Control Motor"
15 is "HVAC Air Inlet Door Actuator" (<-- your diagram of Air Inlet actuator)

If 13 is the blend door that controls outside air mixing, then the wiring diagram is of a different actuator. Do you have a diagram of HVAC Air Adjustment Control Motor?
If 13 is the blend door, what does 15 do? Maybe 13 controls outside air coming in, and 15 controls distribution of that air to top/bottom vents? Or is it something else?

Here's a video showing 15.
Another great video showing various views of 15 (but not 13).

 

[airline tech]

To clarify-Do you have Dual Automatic Controls or Manual Controls with only one temperature control?

Automatic Has:

1. Air Inlet Door Act
2. Air Distribution Act (Vent,Floor,Defrost)
3. 2-ea - Air Temp Door Act (Dr/Pass)

Manual Has:
The same but only (1) Air Temp Door Act

I was looking at another description and it described ground circuit within the FCIM, but was not shown in the wiring diagram, I'm digging into the diagrams and see if I can find us a resolution
You are correct, but you would still have to provide power (draw) with truck off, to hold door closed.

I am a former Auto Tech, but never got into any major repairs, last 30 years Aircraft Tech, aircraft wiring prints provide more detail and allow you to see complete circuit, automotive is sometimes vague

 

[airline tech]

The Actuators are Bi-Directional, Thus Reverse Polarity applies, the feedback circuit tells FCIM the actuator position, and FCIM provides power signal to move the actuator CW/CCW depending on Climate Control (Desired Setting)
I'm assuming you have Dual Climate (Automatic) Control - you should be able to select auto off and then press the Recert (Icon) on touchscreen
Attached is all I can find, related to the system
I was wrong on the door opening with power off, it's full open by the description.

 

[CATX]

“So, if you search mice, you will see the screen add mod you can do to prevent mice from entering cab of truck, they access this area by the cowl drain ends (Left/Right), there is a small area on each end of the cowl (under wiper blades) where they can enter and access the inner cab framework (inlet) to the Cabin Air Filter
The screen mesh inlets (you see) in center of the black cowl are the air inlet for HVAC”

What do you mean left/right ? As I understand there are only two inlet holes, both on passenger side, below the passenger wiper blade. Just to be clear, there are no holes on the drivers side, correct ?

 

[jblc]

Just to be clear, there are no holes on the drivers side, correct ?

Mine doesn't have any on driver's side. They're all on the passenger side (two holes there, a left and right one). Check out the link that i posted above, as those photos may clarify your questions.

I am a former Auto Tech, but never got into any major repairs, last 30 years Aircraft Tech, aircraft wiring prints provide more detail and allow you to see complete circuit, automotive is sometimes vague

Very cool!

I'm assuming you have Dual Climate (Automatic) Control - you should be able to select auto off and then press the Recert (Icon) on touchscreen

Exactly: dual climate auto control.
a) Recirc constantly turns off in any setting except Max AC, so it's essentially a useless button.

b) Also even if recirc didn't turn off by itself, the blend door lets in tons of outside air so the cab has poor air quality above 35-40 mph (as mentioned in my prev post)

Attached is all I can find, related to the system

Thanks i see you even marked a few places...
Fortunately, Climate Control 003 also includes information about the humidity/temp sensor that i was asking about (#151-13), including the wiring color (white/blue, pin 4)

You are correct, but you would still have to provide power (draw) with truck off, to hold door closed.

Agreed. Although, i'm only interested in keeping it closed when climate control is Off and the vehicle is running -- and in those cases power drain isn't an issue.
The humidity sensor hacking route may be best, though, given that the FCIM seems to have a feedback loop to monitor the position and command the motor. So, even if I move the motor manually to close the door, and hack the feedback position to report that position, it's possible the hacked position will not be within the tolerance range...so the computer may throw a code if it sees the door not responding as expected.

 

[airline tech]

True, but if we can figure out way to trick humidly sensor that it needs to keep inlet door closed, then possibly never get a trigger to open

Being that you have a serious issue with smoke, and I do believe that the door while even closed will still allow smokey air in the cab, it's not an airtight seal

Might, just be easier to Alum Tape up the holes that you plan on installing screen, this way as long as that door is opening and closing as intended, there is no sensor that samples the air flowing through it, thus no faults.
But you will possibly have smelly ac at some point

“So, if you search mice, you will see the screen add mod you can do to prevent mice from entering cab of truck, they access this area by the cowl drain ends (Left/Right), there is a small area on each end of the cowl (under wiper blades) where they can enter and access the inner cab framework (inlet) to the Cabin Air Filter
The screen mesh inlets (you see) in center of the black cowl are the air inlet for HVAC”

What do you mean left/right ? As I understand there are only two inlet holes, both on passenger side, below the passenger wiper blade. Just to be clear, there are no holes on the drivers side, correct ?

Ref: Drain L/R - The black cowl cover, covers the forward engine bay to cab framework, rainwater that drops down through the vented screens (In the Balck Plastic) Trim cover, falls into the framework (I'm calling it a trough) on the edges Left and Right-hand sides of this trough there are openings that allow rainwater to drain off to the sides and down by the tires
The openings are large enough for mice to be in engine bay and crawl into this trough, run your hand along the edges of the black plastic cowl covering and you will feel it.
Pour a cup of water down in the (Vent Screen) and you can see the water flowing down by the tires.

Now directly behind this trough (above) are cutout openings in the framework that allow the air that is drawn in to be forced into the HVAC -Outside Air Inlet. On Passenger Side Only
Being the door hangs open, with truck shut off, mice have access to cab, by crawling through cutout and through open door

From the door, they can access cab directly, Cabin air filter, blower motor and your ac duct work and somehow are accessing the area under the center console as others have posted pics of treats, they left behind under it, there appears to be a small valley for wire harness run by the pics i have seen

 

[airline tech]

I wonder how it would work if you moved the pins 3 & 7, this should drive it closed when off, but it will most likely trip fault, and with it on it would be open and cycle closed.
Reverse your issue

Just a thought

 

[jblc]

True, but if we can figure out way to trick humidly sensor that it needs to keep inlet door closed, then possibly never get a trigger to open

I'm thinking of having a "manual override" recirc switch. When Off, the system is in default stock state. When On, it forces a low humidity reading. So, it won't become stuck permanently.

Being that you have a serious issue with smoke, and I do believe that the door while even closed will still allow smokey air in the cab, it's not an airtight seal

The doors aren't substantially leaking (see first post), and i've tracked it down mainly to the HVAC system.

Might, just be easier to Alum Tape up the holes that you plan on installing screen, this way as long as that door is opening and closing as intended, there is no sensor that samples the air flowing through it, thus no faults.
But you will possibly have smelly ac at some point

True -- Al taping over would work in some cases (good thought). I'm concerned about accidental blend door motion and overloading the blower motor...also, I might not notice when this happens.
I would hope there's an manually activated version of this, eg humidity sensor. If super smoky then keeping HVAC off and taping over could be a solution temporarily (again, good thought)

I wonder how it would work if you moved the pins 3 & 7, this should drive it closed when off, but it will most likely trip fault, and with it on it would be open and cycle closed.
Reverse your issue

Just a thought

Yeah, it's a good thought. Here was my thought on this from my last post:

...though, given that the FCIM seems to have a feedback loop to monitor the position and command the motor. So, even if I move the motor manually to close the door, and hack the feedback position to report that position, it's possible the hacked position will not be within the tolerance range...so the computer may throw a code if it sees the door not responding as expected.

To augment that, I think the air inlet feedback system would have an unexpected -1x sign if reversing motor inputs, so the system will go unstable and break (even if not throwing a code), given that the documents describe a reference command --> motion --> sensor comparison feedback loop.

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