A silly thing happened to me relating to my SC recently so am sharing just that you know & avoid the “trap”.
Last week, I noticed a slight whistling noise inside the car & noise grew louder n piercing when I turned up the aircon volume. But no noise when I turned off the aircon. I rang my mechanic & he suspected a faulty blower. I then drove over to see him. He simply flipped open the aircon air vent on the passenger side & bingo the noise disappeared. The vent was closed & caused uneven air flow. We had a good laugh & I was very thankful not having to replace the blower. LOL

 

Thanks for this tip. Was having the same problem, trying to decide if I needed to go to a Lexus dealer or indie shop to have resolved. Procrastinated by keeping the airflow level at a slower speed but your info solved the problem...Much apreciated.

 

Probably the foam seal around the vent and between the vent and dash has deteriorated. So when the vent is closed, it forces the air out the sides. But just a wild guess.

 

Thanks. Will check on this too.

 

Great. Am glad that it was of help.