HVAC whistling sound

[trey_is_a_jedi]

I am the proud owner of a new Offroad shortbed. The truck is great however something I didn't notice on the test drive or in my time fiddling with it before buying was a slight whistling sound in the HVAC. Wondering if anyone else has noticed this. I saw on the tundra forum and toyota forums in general others have noted similar issue. I've narrowed down the settings to reproduce. I am hoping with some time of it breaking in that it may go away.

1. Fan settings in the middle range notch 3/4/5
2. Vents on upper only
3. Air conditioning or auto-climate on

I notice the sound appear around notch 3 fan speed and go away when I go to max fan speed. It is a high pitched but not loud noise and it is a whistling sound. It goes away immediately when the AC is switched off or if I switch AC to max as max setting does something with with moving the flaps internally. Its warm here so I haven't tested it with heat on. The noise isn't present when using any other setting...just top vents only. I have also tried opening/closing vents and it doesn't seem to resolve it completely.

Figured i'd start a thread. I'll take it to the dealer after a bit if it doesn't improve. I've only had it one day so might just be breaking in stuff. After a bit of fiddling changing the settings... going to ac on/off and to max etc I noticed it go away but I expect it will come back.

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[trey_is_a_jedi]

Just bumping my own blog here on the hvac whistling.

Talked to the service manager at the dealer and they said that no the whistling wasn't a feature that was supposed to be included in my tacoma. I am taking it in on Thursday for the diagnosis and then figure out what the next step is. I'm really hoping its some debris or something but I fear the mixer flap(s) are the issue maybe ill fit or just bad parts.

Some updates on how to reproduce.
- Upper vents only
- Temp setting at ~72, ac on or off or heat doesn't matter
- Fan speed 1 notch below max is loudest, gets quieter 2-3 notches down and below that disappears.

 

[mitchfon]

I have the exact same thing. I will mention it to them on my first service appointment. Let me know what they find!

 

[Supertech1]

Same with mine. Also same as my previous truck, 2023 Tundra

 

[trey_is_a_jedi]

Just an update. The dealer service manager sat in the truck and acknowledged the sound. They took the truck back and diagnosed it and came back with the following.

1. They believe the entire dash may need removed and advised removing the dash could cause issues down the road with rattles.
2. They could replace the vent/flapper box but they can't gaurantee it would fix the sound
3. They then wrote down the techs said they couldn't hear it even though I demonstrated it. So the tech's wrote down 'works as designed'.

I called back and challenged that statement and they said just bring it back if/when I would want to push forward with requesting Toyota approve the dash being pulled and the heater box/flaps etc be replaced.

I called Toyota corporate and am escalating with them directly. I agree removing the dash is drastic so i'm going to wait a bit and see where things go. I won't be going back to dealer 1 though as I have lost some trust with them for acknowledging then not acknowledging the issue.

 

[mitchfon]

Just an update. The dealer service manager sat in the truck and acknowledged the sound. They took the truck back and diagnosed it and came back with the following.

1. They believe the entire dash may need removed and advised removing the dash could cause issues down the road with rattles.
2. They could replace the vent/flapper box but they can't gaurantee it would fix the sound
3. They then wrote down the techs said they couldn't hear it even though I demonstrated it. So the tech's wrote down 'works as designed'.

I called back and challenged that statement and they said just bring it back if/when I would want to push forward with requesting Toyota approve the dash being pulled and the heater box/flaps etc be replaced.

I called Toyota corporate and am escalating with them directly. I agree removing the dash is drastic so i'm going to wait a bit and see where things go. I won't be going back to dealer 1 though as I have lost some trust with them for acknowledging then not acknowledging the issue.

Let us know what happens with corporate. That was my worry was having to pull apart the whole dash. Maybe Toyota can provide us with some sort of compensation.

 

[trey_is_a_jedi]

Here is a short clip of the whistle. I am starting at zero and turn the fans up to 1 notch below max. I think you'd need headphones or just a quiet room and the volume up to hear it. Is this what yours sounds like?

Also I realize maybe some people's ears might not notice this idk. its been apparent to every person who has sat in my truck though.

 

[PaulT]

I hear it in ur video…sounds like a kettle of water heating up to steam. Faint but it’s definitely there.

Pretty sure I don’t hear it in mine. Will check.

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