Blower Motor Stuck In Between Everything; No Air Out Any Vent

[Raacerx]

I've got a nasty issue with my 2021 Ranger Tremor; when it is over 90*F out, and I am going over 75MPH fully loaded up, the blower motor gets stuck in between all of the vent outputs.

I can hear the motor going full blast. The dash gets ice cold. But no air comes out of the defrost, the main vents, or the foot vents.

No amount of changing buttons, slowing down, turning AC on and off fixes it. Have to pull over and wait 15-20 minutes to either cool down or heat up.

It only occurs after a few hours of continuous driving, at like 74mph or above.

Things to note, I have an aftermarket bumper and skid plate. Engine temp is fine. There are no codes. I travel with a rooftop tent, cargo basket, and about 500 pounds of additional gear.

Could my minimal bumper be allowing too much air into something at 75mph?

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[9zero1790]

could it be the blend door stuck? its a semi common issue with the 5g trucks.

 

[airline tech]

Are you saying no code just by dash light?
If you were to put a scanner on it able to read (B) codes I am sure something will show

now possibles:
Blend Door / Actuator- this is what moves air distribution around, either binding or losing control

Temp - Humidity Sensor - in auto mode this sensor is vital control for all actuators.
If you look above your right knee- the little vent in the dash trim is the inlet for that sensor.

Evap freezing up - either clogged drain or low on Freon. There is a temp sensor in the core housing, might be forcing airflow to only the evap core.
I would have to check manual for sure operation.

Most likely this by your description of when it does it.

now this is where the new bumper comes into play, was any of the original airflow blocked across the condenser coil, if so it may be the cause, ineffective heat removal at the condenser, then travels to the evaporator and causes freezing over of the evaporator.

Another possibility is clogged cabin filter or mouse / rat has made a home on it.


Try operating in manual mode only, see if it makes difference.

when you shut truck off , either the evaporator is warming up allowing operating or the modules are going to sleep, fault resets after module shut down (sleep mode) 10-15 minutes

 

[GhostStrykre]

My blend door got stuck and things got weird. My passenger side had heat and my driver slider did not (this was January in ohio). I remember hearing the blower motor running but it just wasn’t blasting heat like it should have.

as mentioned, it’s semi common. Common enough that I was out of warranty and ford customer service still picked up like 90% of the tab. Not everyone has that luck tho.

Best of luck to ya! I really hope it’s a simple fix. I think my initial quote was $3,500 to repair (11 hours of labor to pull the entire dash).

 

[airline tech]

After checking the wiring manual, the Evap sensor ties into all the Climate Control actuators but its function is to disable the AC compressor in the event of frozen evap core.

So, to pinpoint this down you will need a code, as there are a number of possibilities. So, either the Air Dist Door Actuator is failing or another actuator or temp sensor in the system is failing, and you are seeing the Air Dist Door actuator get lost as to what position it is supposed to be in.


This system uses a 5-Volt reference circuit, and all sensors and actuators are communicating on that circuit for control. Something is dropping out of the circuit and it's losing the communication.
It is a very complex system.

 

[Raacerx]

I guess I wasn't searching the right term "blender" because I didn't find all that many references to the same problem.

To me it sounds like yes, the "blender" or whatever is stuck in between or rolled back or something. I know that it is producing cold air, but none of it is getting into the cabin. But the odd thing is that I can still hear it moving when I adjust between the defrost/main/foot, yet it no air comes out.

I have FORSCAN, and nothing has come up related to this.

When it occurs, it happens over a few minutes, where the blower motor is still going, air is still ice cold, but the airflow starts to lower and lower and lower until you suddenly realize you're quite warm and there's no air blowing.

I tried to do a test one time when it happened where I left the compressor off, and I couldn't replicate, so it seems to only happen when the compressor is in use.

 

[Raacerx]

BTW the truck just came back from the dealer for this issue, second time I've taken it in, and they too have found zero codes. Of course they said they haven't heard of this issue...

 

[airline tech]

Ok, No Codes-Hmm

By your OP, I now wander if it (Airflow) related, and being that it happens when driving at hi-way speeds.

As a normal driver, you set your comfortable temp selection and leave it, and only change it between seasons, leave it in (Dual-Auto) - (My Normal)

So, minimal movement for the door actuators, once the temperature selected and the actual temperature of the cab has been reached.

Now let's bring in the airflow and think about what it's doing in the HVAC box.

The temp humidity sensor, is the feedback sensor for cabin temp (Temp-Wise)
The other half of that sensor is Humidity - A humidity increase will trigger the Air-Inlet door (Recirculation) to Open, and when it opens it is on an approximant (5-Minute) timer and will close after 5-Minutes.
This is the only door that will cycle (full- open / close) during a drive cycle without major selected temp changes.

Now, I will have to play with my (Recirculation) button to be sure, but I think when that door cycles there is a brief moment (seconds) where the airflow is disrupted until that door movement has completed.
This may be causing your issue, and it gets lost during this transition.

Try playing with the (Recirculation) button to see if you can force fault the system plus pay attention to the sound it makes when cycling, you should barely notice it (noise wise)
Note: In Max-AC, Defrost, or Max Defrost this door is disabled and will not move by manual selection (closed) (Recirculation- Mode)

Now, Airflow at Hi-Way speeds flowing through the HVAC housing will affect the Air-Inlet door as there will be an external (airflow) force against the door itself, the actuator may not be strong enough to overcome it and gets stuck in between movement. (Bad-Actuator Gearing or Binding Air Inlet Door)

The Air-Inlet door also (communicates) to the Air-Distribution door on its position.

The Air-Inlet door is directly behind the glovebox and easily accessible, you can see the big vent for it, this vent brings in outside air when open and when closed it is recirculating 90% of the cabin air - as this door is not designed to fully close and always bring in 10% outside air.
Many complains about that design (mainly wildfire smoke) areas as this will always allow smoke into the cab with (zero) way to stop it.

I do not think the Air-Distribution door itself is the issue as once it is in selected position then it will not move unless major changes to selected temp have occurred.

All of the door actuators operate (move) by a momentary power being applied to move the door once the door has reached its commanded position the power is removed, and the door is held in this position by the internal gearing of the actuator. (The Power / Ground) for these are reverse polarity - to drive the doors CW / CCW.

I am curious if you were to hook up Forscan while it is failure mode if it will show any codes, since it is not showing any codes after a power cycle, this will have to be done before the truck is shut off and the fault allowed to reset.


Air Inlet Door Actuator (Manual Description)

The air inlet door actuator contains a reversible electric motor and a potentiometer. The potentiometer allows the FCIM to monitor the position of the airflow mode door. The FCIM drives the actuator motor in the direction necessary to move the door to the position set by the recirculation button and when the MAX A/C , Defrost or MAX Defrost buttons are selected.


(set by recirculation button = you manually selecting it closed / open)
In Max AC , Defrost or Max Defrost the door is commanded closed automatically) and cannot be commanded to open by the recirculation button (Touchscreen) button is greyed out.

In normal AC (non-max) the inlet door will automatically cycle open and closed depending on cab humidity level being read by the Temp-Humidity sensor.
This is where I believe the issue (fault) is occurring and where I would focus on.

 

[airline tech]

Other things to try,
Pull out and clean Humidity - Temp sensor , may try blow gun with a low pressure and blow through inlet vent

When it fails - note if any abnormal selected temp or (OAT) outside temp indications

 

[Raacerx]

For better or worse, it's not an easy thing to recreate, and not one I enjoy recreating either.

If it was speed related, I would think that slowing down to a lower speed would allow it to "free itself" or something or other, but it's been insistent on not ever improving until I turn the vehicle off and wait.

When you turn the truck off, do any of these motors cycle into a different position? Does something open that's maybe closed, or vice versa?

I've tried stopping, turning the car off, stepping outside, waiting a minute, and starting back up and the problem had not fixed itself. It takes at least 15-20 minutes.

But I've never heard anything stuck or struggling. I certainly have tried engaging and disengaging the recirc, and I've also tried defrost, although perhaps not Max Defrost.

 

[airline tech]

When the truck is turned off, all actuators are momentarily provided power to cycle them to the at rest position, such as the air inlet door will power command to the open position, not sure where the others go.
Now when a fault is generated in the FCIM, the FCIM is the control module for the climate system it will deactivate the faulted components until fault resets itself.
The FCIM will hold this fault in memory until it fully powers down, this being the 10 to 20 minutes, now in sleep mode.
I will have to look which fuse , but you may try pulling for a few minutes and see if you get a quicker reset.
The biggest issue here is the FCIM has FET protection, if enough fault events have occurred then the FCIM will fully lock out that failed circuit and force FCIM replacement.
The FET is basically an internal circuit breaker , and if the fault is caused by a short circuit, it is shutting down the circuit to protect the FCIM internally.
That is why a code retrieval is important in this matter.

 

[airline tech]

I am going to backtrack here and go back to my first post.
And the kicker is when you say it only happens with AC on.

I am 100% certain on this:

The EVAP is freezing up and blocking the airflow, you hear the actuator moving but cannot feel it.

So either Low on Freon or clogged drain

Do you ever see any condensate drainage from truck?

I am guessing (no) as this is somewhat common from factory.
I think mine is clogged as I don’t see any drainage in mine , no wet floorboards thankfully.
I need to get my blow gun out and shoot some air through it. To check
You will need to use search feature here to find location - it’s hidden just above transmission at the firewall .
I have to find the drain myself

and you may try - removing the skid plate you added to see if the airflow change at the condenser is causing the Evap to freeze over.
This may be the cause - worth a try

 

[airline tech]

To note all incoming air into the HVAC box, passes through the Evaporator, if it becomes blocked you are blocking incoming air, thus the reason for the blower motor to ramp down in speed.
and since the air is not passing through the EVAP, it cannot reach the air outlets.

The long drives at Hi-Way speeds lets it build up (ice).

Now all that needs to be done is find the reason for it happening.

1. Improper airflow across Condenser, depending on what you changed / modified from OEM
2. Sometimes a skid plate (add) can create an airflow disruption, by not allowing airflow to completely flow through the condenser, same with aftermarket bumper.
I am throwing this as a possibility - due to problem arises on Hi-Way drives.
3.. Leaves / Debris stuck between Condenser / Radiator
4.. Low On Freon
5. Clogged Cabin Filter (Restricted Flow) across the Evaporator Core
6. Clogged Condensate Drain , pools up around Evap and freezes
7. Failed Evap Temp Sensor (should throw code) - so not likely but possible
8. Failed Thermal Expansion Valve

This is all the possibilities of the Evap Freezing up.
Sorry it took me a bit to finally see what was happening here and am 100% sure this is your issue.

The most likely on this - with it being only after long drives (noted) will be a clogged or slow draining condensate drain. As humidity is being dropped off of the evaporator (dripping) over a long drive it builds up and pools around the Evap this pool over a long drive will allow the Evap to freeze over.
So make this a must check this drain - step as I highly think this is it.

 

[Big Blue]

I would definitely take it in and have the refrigerate level checked. If you Google "AC freeze up" it is almost exclusively the first issue that comes up. This is followed by air flow over the evaporator coil, plugged cabin filter, blocked vents. The coil freezing up is a self fulfilling event as it blocks the air flow as it freezes. Also explains the dash feeling cold and the length of time to reset. You have a block of ice in there that needs to melt.

I don't think you bumper or other front mods have anything to do with this. Many others have done similar without issue. The condenser coil is not mentioned in any discussions on freeze up. It would cause lack of cooling efficiency, but not coil freeze up. You would also see issues with engine coolant temp, which you say you don't.

 

[Raacerx]

The truck was in the dealer last week for this exact issue (and some other stuff), and they said they checked the whole A/C system, and I can see evidence of that.

I'm not a huge fan of this dealer, so it's not like I trust them, but they said they can't do anything without a code.

If its freezing over, wouldn't this throw a code?

A lot of other people do have front bumpers and no issues, but I do wonder how many of them are going over 75MPH in 100*F degree weather for 5+ hours?

Here is a pic of the front bumper.

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