Loud whining noise when the A/C is running

[A1onpoint]

I have a 2023 suburban. For the past 4000 miles when turning on the A/c there's this really annoying whining sound almost like a high pitch/frequency type of noise, took it to the dealership and they say they didn't hear anything.
When the air is on and the A/c is off then there's no whining noise, but as soon as I turn the AC on the noise come back. It especially noticable while driving and letting off the gas pedal at different RPM, the noise can gets really loud. What can cause this?

 

[Doubeleive]

I was having a wierd noise on my 18 recently sounded like something in the air vent or maybe the cabin air filter area, turned out my wife had closed the far right vent near the passenger window and the air being blocked was making a higher pitched whine type noise, opened the vent and noise gone.
might be worth checking to be sure all the vents are open, it was driving me crazy

 

[Tahoe14]

You could ride with the service tech or service manager and point out what you are hearing.

 

[Dayzoo]

Any chance your cooled seats are running at the same time? I can always tell by sound if the cooled seats are on...

 

[A1onpoint]

Thanks guys but definitely not the air vent nor the cool seats. When the AC is running and if you toggle the "A/C" button off but the air is still blowing in the car, the noise goes away immediately. Toggle the button on and the high pitched noise comes right back, must be the compressor/belt because when driving the SUV the noise would get louder depending on the RPM. I will have to schedule another appointment with the dealership and figure this out.

 

[Geotrash]

Thanks guys but definitely not the air vent nor the cool seats. When the AC is running and if you toggle the "A/C" button off but the air is still blowing in the car, the noise goes away immediately. Toggle the button on and the high pitched noise comes right back, must be the compressor/belt because when driving the SUV the noise would get louder depending on the RPM. I will have to schedule another appointment with the dealership and figure this out.

Could be the compressor but the cooling fans also may come on when the compressor is on. Pop the hood and listen to where it's coming from and let us know. Or take it to a different dealer.

 

[posttal]

Did you ever solve this issue ?...I'm having the EXACT same thing going on in my 2018 Yukon..I've gone over the A/C compressor and lines with a stethoscope and cant fine anything wrong . And yes it sounds like a high pitch/frequency type of noise ONLY when the A/C is on..goes away if you crank up the heat or push the button to turn off the A/C