Whistle from HVAC while in footwell-only mode

[Murds]

Picked up a new LC in October. We had a warm Fall in the NE but now in full heat season. At first I thought I had a door or sunroof seal issue but I have a whistle that is the actually from the HVAC. Easiest described as the sound when one of your windows isn't quite rolled up all the way at highway speeds. After chasing it down there is an obvious whistle coming from the center dash vents when HVAC is set to footwell only mode. In any blend mode (footwell+dash vents or footwell+defrost) or full on dash or defrost it is whisper quiet. I decided to look here to see if anyone else had the issue or maybe there is just a defect with mine. I saw a reference by @Meteor to it in this related heater thread, so this is a design/manufacturing issue. I stuck my boroscope down the center vents to see what I could see. There is a horizontal cylinder with different fluting that rotates its position depending on the mode. No obvious issue. Talked to my buddy who is a Lexus mechanic. He said that the blower box is a unit, and you have to rip the whole dash off to get to it. I am not in a big hurry to have that happen to a truck with 500 miles on it.

Post back if you have the issue and even better if you have had Toyota look at it. If enough people have this issue I will approach Toyota for them to launch an investigation and maybe get a TSB.

 

[RRanger1996]

I have a whistle coming from the driver side vent to the left of the steering wheel. I have my 6 month maintenance appointment next week and will inform the dealership at that time. If I close the vent, its not an issue and that's been my current workaround.

 

[Kevin]

I'm having the same issue. A whistling sound when the heat is set to only blow out the floor vents just as you described. I haven't talked to my dealer about it, but I'll mention it when I have my first service appointment. However, that is probably 2-3 months away at this point.

 

[Madscientist]

My rig does the same- somewhat high pitch whistling noise when HVAC system is directed 100% to footwell space- much quieter when routed through all other venting options.

 

[uraniumrich]

Picked up a new LC in October. We had a warm Fall in the NE but now in full heat season. At first I thought I had a door or sunroof seal issue but I have a whistle that is the actually from the HVAC. Easiest described as the sound when one of your windows isn't quite rolled up all the way at highway speeds. After chasing it down there is an obvious whistle coming from the center dash vents when HVAC is set to footwell only mode. In any blend mode (footwell+dash vents or footwell+defrost) or full on dash or defrost it is whisper quiet. I decided to look here to see if anyone else had the issue or maybe there is just a defect with mine. I saw a reference by @Meteor to it in this related heater thread, so this is a design/manufacturing issue. I stuck my boroscope down the center vents to see what I could see. There is a horizontal cylinder with different fluting that rotates its position depending on the mode. No obvious issue. Talked to my buddy who is a Lexus mechanic. He said that the blower box is a unit, and you have to rip the whole dash off to get to it. I am not in a big hurry to have that happen to a truck with 500 miles on it.

Post back if you have the issue and even better if you have had Toyota look at it. If enough people have this issue I will approach Toyota for them to launch an investigation and maybe get a TSB.

Yup. Even at the low speeds the blower is very loud. I was wondering if I might have an issue with the damper switching between the different modes (def/dash/feet vents). But, I think it might just be poor design.

 

[MrBrownSugar]

Same here on a 2024 1958.

The noise is coming from behind the front vents or behind the middle/central display.
There is even a secondary whistling component mixed with the main sound of air flow.
Here is a recording of what I hear on mine -

Murds, thanks for pointing me to this thread. And cool idea with the horoscope. If you still have it, it will be interesting if you can loop it through the floor vents and see if there is anything obstructing the airflow. Even though it doesn't sound like an obstruction - more like an actuator/door not completing its motion.

Btw, not sure if you have seen this thread on Tundra. Sounds similar. AC/Heater Whistling

 

[Murds]

Same here on a 2024 1958.

The noise is coming from behind the front vents or behind the middle/central display.
There is even a secondary whistling component mixed with the main sound of air flow.
Here is a recording of what I hear on mine -

Murds, thanks for pointing me to this thread. And cool idea with the horoscope. If you still have it, it will be interesting if you can loop it through the floor vents and see if there is anything obstructing the airflow. Even though it doesn't sound like an obstruction - more like an actuator/door not completing its motion.

Btw, not sure if you have seen this thread on Tundra. Sounds similar. AC/Heater Whistling

I did try and go up through the floor vents. I couldn't get a clean look at anything, too many turns. Best guess is the cylinder is not rotating to the proper spot or they put in small bypass holes for some minimal airflow to the center vents not planning on it sounding like forcing air through a crack. With enough folks reporting it we can go to Toyota and have corporate open a case. This may be one of those problems solved by turning the radio up...