No Air Flow to Rear Floor Vent

[Awirez]

It seems I am getting no air flow to the rear floor vents. Picking up from my post about the lack of rear passenger vents for NA, when the other post inspired me to test the rear floor vent...
https://www.ranger6g.com/forum/threads/what-gives-no-rear-a-c-vents.7438/post-304064

I chatted with Ford. They gave me a case # and advised I go to the dealer to have it looked at. From my investigating, it's not working as it should.

Unfortunately, there is some chatter on the Bronco6g forum about this issue as if it a design or programming flaw that Ford will not address.

I don't have the ability to perform whatever technical testing needs to be done without schematics. I browsed the 2024 parts pages to get a reference of items involved with the blend doors. It appears there is a specific floor vent blend door. I have a reference to the parts on the 2024 year below. My hope is it is a simple as a replacement or recalibration of the floor vent blend door. Last night I tested by changing modes manually (defrost, dash, floor) to see if there was any movement of this actuator. Changing through all vent modes the actuator never moved. This actuator is in a hard to see spot on the driver's side of the evaporator/distribution assembly.

Anyone else have a similar problem?

2024 Ford Bronco blend door not working floor mode door actuator not working

https://www.bronco6g.com/forum/threads/air-recirculation-not-working.26070/post-1350941

https://www.bronco6g.com/forum/threads/2025-rear-ac-vents-not-working.114557/

ttps://www.bronco6g.com/forum/threads/ac-not-working.39736/post-2561256

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[Awirez]

Before going to the dealer I figured I'd investigate for myself by looking at the Ford Service Info. I was wrong, what I pictured before controls the passenger blend temperature.

The info for Automatic Temperature Control Operations is below. I'd imagine I have air blowing out of the "side window demisters" may be due to the humidity and air temp. I'm in central SC and it's HOT and HUMID. Perhaps in the logic of the HVAC Control module. Or, a programming error of the mode door actuator positioning based on mode selection. Maybe it is what it is, and one cannot expect any cool air to be directed to the rear floor vents. ? I believe it would have to be a Ford engineer to explain why air is coming out of the side window demisters when the FLOOR setting is selected.

Can anyone else in the hot South confirm similar results when the HVAC is set to: AUTO - OFF, Temperature - ANY, Vent Setting - FLOOR? Is there a fair amount of air flow out of the front floor vents and side window demisters?



Air Handling

There are 4 door actuators that control the ATC HVAC system air flow into the passenger compartment:

• Air distribution
• Air inlet
• Driver temperature
• Passenger temperature

All of the door actuators contain a reversible electric motor and a potentiometer. The potentiometer circuit consists of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal to the HVAC control module from the contact wiper indicates the actuator door position. The HVAC control module powers the actuator motors to move the doors to the desired positions. The desired door positions are calculated by the HVAC control module based on the set temperature, in-vehicle temperature, and ambient air temperature.

When an airflow mode, desired temperature, fresh air, or recirculation mode is selected, the HVAC control module moves the actuator motor in the desired direction.

The HVAC control module sends a PWM signal to the blower motor control module to regulate the blower speed as necessary. The blower motor control module provides voltage to the blower motor based on requested PWM duty cycle from HVAC control module. A delay function provides a gradual increase or decrease in blower motor speed under all conditions.

AUTO

When AUTO is selected:

• the HVAC system operates in a manner to achieve and maintain the temperature set by the operator.
• the air inlet door actuator is automatically controlled by the HVAC module based on the temperature setting.
• the mode door actuator is automatically controlled by the HVAC module based on the temperature setting.
• the temperature door is automatically controlled by the HVAC module based on the temperature setting.
• the A/C compressor is automatically controlled by the HVAC control module based on the temperature setting. The A/C compressor does not operate if the outside temperature is below approximately 32ºF (0ºC).
• the blower motor speed is automatically controlled through the blower motor speed control when it receives a PWM signal from the HVAC control module based on the temperature setting, but can be manually adjusted if desired.

OFF

When OFF is selected:

• the recirculated air request button is disabled.
• the A/C request button is disabled.
• the air inlet door closes, preventing outside air and allowing only recirculated air.
• the blower motor is off.

Max A/C

When MAX A/C mode is selected:

• the air distribution doors operate simultaneously to direct airflow to the instrument panel registers. A small amount of airflow from the floor ducts are present.
• the temperature door moves to the full cool position.
• the blower motor is commanded to the highest speed, but can be manually adjusted if desired.
• the air inlet door closes, preventing outside air and admitting only recirculated air.
• the recirculated air indicator is illuminated (recirculated air forced on).
• the A/C button is illuminated.
• the A/C compressor operates if the outside temperature is above approximately 32°F (0°C).

PANEL

When PANEL mode is selected:

• the mode doors direct airflow to the instrument panel registers. A small amount of airflow from the floor ducts is present.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

PANEL-DEFROST

When PANEL-DEFROST mode is selected:

• the mode doors direct airflow to the instrument panel registers, the defroster duct and the side window demisters.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

PANEL-DEFROST-FLOOR

When PANEL-DEFROST-FLOOR mode is selected:

• the mode doors direct airflow to the floor ducts, instrument panel registers, the defroster duct and the side window demisters.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

PANEL-FLOOR

When PANEL-FLOOR mode is selected:

• the mode doors direct airflow to the floor ducts and the instrument panel registers.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

FLOOR

When FLOOR is selected:

• the mode doors direct airflow to the floor ducts.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

FLOOR-DEFROST

When FLOOR-DEFROST is selected:

• the mode doors direct airflow to the floor ducts, the defroster duct and the side window demisters.
• the recirculated air request button can be enabled, but can automatically turn off.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

DEFROST

When DEFROST is selected:

• the mode doors direct airflow to the defroster duct and side window demisters. A small amount of airflow from the floor ducts is present.
• the recirculated air request button can be enabled, but can automatically turn off.
• the A/C is automatically commanded on and remains on until the system is either turned off or the airflow mode has changed and the A/C button is pressed.
• the A/C compressor operates as long as the outside temperature is above approximately 32°F (0°C).
• the blower motor is on and the speed is adjustable.
• small airflow from panel and floor outlets will be present.

MAX DEFROST

When MAX DEFROST is selected:

• the recirculated air request button is disabled. The air inlet door opens, allowing only outside air into the passenger compartment.
• the air distribution doors operate in combination to direct airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct is present.
• the A/C is automatically commanded on and remains on until the system is either turned off or the airflow mode has changed and the A/C button is pressed.
• the A/C compressor operates as long as the outside temperature is above approximately 32°F (0°C).
• the temperature is set to the highest setting and is not adjustable.
• the fan is set to the highest speed and is not adjustable.
• the heated rear window and heated mirrors also turn on when you select maximum defrost.

Cowl Pressure Blower Motor Strategy

When the climate system is in outside air mode (air entering the cowl air inlet), the air pressure increases as vehicle speed increases. The change in pressure is a function of vehicle shape. The change in pressure effectively changes the airflow into the vehicle.

If the vehicle is equipped with EATC , there are calibration strategies that help reduce the effect of cowl pressure. The blower motor slows down to offset increased cowl pressure as the vehicle speed increases until it reaches minimum voltage. However, for vehicles with a high cowl pressure effect, the changes in airflow may still be perceived by the customer. If the HVAC has a variable outside air inlet door (such as the Mustang Mach-E), then the EATC can control the cowl pressure to reduce the airflow entering the vehicle.

Vehicle Door Closure Actuator Feature Strategy

During normal operations when the vehicle key is selected OFF, the recirculation door actuator moves to the mid-position to allow pressurized air within the vehicle to escape and aid in the closing of the vehicle doors. After a predetermined time, after the vehicle key is switched OFF, the recirculation door actuator returns to the closed position.

Remote Start

Remote start is an optional feature available on this vehicle. In addition to being able to start the vehicle remotely, the remote start feature also utilizes other vehicle systems to increase the level of comfort to the vehicle occupants upon entering the vehicle. Additional information on the remote start feature and the other vehicle systems, refer to Owner's Literature.

When the factory remote start feature is used, the climate control system runs at the setting it was set to when the vehicle was last turned off. This feature is enabled through the information and entertainment display unit settings.

Auto Settings

• Access the vehicle drawer on the touchscreen,
• Press SETTINGS.
• Press Vehicle.
• Press Remote Start Setup.
• Press Auto settings.

Last User Settings

• Access the vehicle drawer on the touchscreen,
• Press SETTINGS.
• Press Vehicle.
• Press Remote Start Setup.
• Press Last settings.

 

[XORegonian]

I get a lot of air flow through the window demisters on my Lariat with the setting to floor as well. I also live in SC near Greenville.

 

[Awirez]

That's what I was figuring. ?

Anyone else?

 

[Sparky62]

I get a lot of air flow through the window demisters on my Lariat with the setting to floor as well. I also live in SC near Greenville.

Same here, but very little air flow from the vents under the seat, what a disappointment.

 

[Awirez]

I suppose I'll find out in Winter, or if I get a response from calling Ford CRC when I have the time.... My theory is that the rear floor vents are only used for heat when the outside ambient temperature is below a setpoint and/or below the truck's interior cabin temperature. Humidity may play a role as well since there is a sensor for that. Presumably, even when set to AUTO the heated air in these conditions should come from the floor and/or windshield/demister vents.

Logically, this would make sense if Ford's focus were to circulate conditioned air in the cabin based on humidity and ambient outside air conditions. ? Cold air drops, hot air rises.

 

[maus92]

I live in a hot/humid forested area very close to an inland bay and the ocean. All I can say is that the A/C in my Lariat is the coldest I've ever had in a vehicle. Nobody sits in the rear, so I cannot vouch for its performance in that area, but I have to bump the temp up to 75, set fan speed to 1, and redirect the upper vents away from me, lol.

 

[LeeHo]

Awirez - Excellent explination. This all leads me to believe that the engineers who carefully crafted and created the #1 best selling midsize pickup in America were all members of the elite FFU team.

 

[1996-to-2025]

I have to bump the temp up to 75, set fan speed to 1, and redirect the upper vents away from me, lol.

Same.

 

[mrmike7189]

Awirez - Excellent explination. This all leads me to believe that the engineers who carefully crafted and created the #1 best selling midsize pickup in America were all members of the elite FFU team.

Edmunds 2025 Truck of the Year= Ford Ranger

 

[cyterio]

I too get limited air (heat or AC) from my rear floor vents in my Ranger Raptor.

I mentioned the AC in an earlier reply, but my kids mentioned earlier today that it was cold in the back seat and I had them test the rear floor vent air flow and they said it was non-existent even when setting the fan to high and selecting only floor.

Can anyone confirm they get any kind of flow from the rear floor vents in their Ranger?

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