Climate recirculation whistle/noise

Sierra20-20 · June 29, 2020

I have a strange whistle noise but it’s only when the AC compressor is on. High pitch, just enough to be noticeable in my opinion. People in my truck don’t notice but once you hear it, can’t not hear it. Service told me it was normal and I did hear it in all there truck. I thought it was just a loud ac compressor/bad insulation/belt. I also have brake issues. I have a strange vibration on the brake pedal when applying very slight pressure. It’s like a tingy/knocking on at a certain sweet spot of pressure. Service said they couldn’t find the issue last Friday. I picked up the truck and drove it home and i could immediately find the spot again. Called them just now and sent them the video, awaiting a call back.. i have 600miles on my 2020 SLT

Dhxrris · June 29, 2020

My brake issue is the exact same. They just keep giving flash updates an it doesn’t do anything. The ac does it about half the time with just the ac home but does it 100% of the time with recirculate on!

Edited June 29, 2020 by Dhxrris

Sierra20-20 · June 30, 2020

O really ?? That’s crazy!! I’m waiting for the manager to call me. I sent them a video of it happening (they said they didn’t see or hear anything).. I’m like.. no, there’s a problem, and you need to fix it.. said they would call back likely tomorrow. Interesting that we have the same issues.. I’ve heard ABS issues might be it or vacuum based on an auto guy not GmC.. I’m hoping they fix it like tomorrow. It’s annoying. Are you taking yours in ? They said it’s new to them. I googled it and they did a massive recall a couple years ago for abs and break issues.. I wish I would have known that before. But I would assume based on that alone, they should be working diligently to get it handled. Wish I could send you the video of mine. It won’t let me upload it

GMCustomerService · July 1, 2020

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Aleigha W.

2016 Sierra Owner · July 1, 2020

On 6/29/2020 at 8:20 PM, Sierra20-20 said:

O really ?? That’s crazy!! I’m waiting for the manager to call me. I sent them a video of it happening (they said they didn’t see or hear anything).. I’m like.. no, there’s a problem, and you need to fix it.. said they would call back likely tomorrow. Interesting that we have the same issues.. I’ve heard ABS issues might be it or vacuum based on an auto guy not GmC.. I’m hoping they fix it like tomorrow. It’s annoying. Are you taking yours in ? They said it’s new to them. I googled it and they did a massive recall a couple years ago for abs and break issues.. I wish I would have known that before. But I would assume based on that alone, they should be working diligently to get it handled. Wish I could send you the video of mine. It won’t let me upload it

The new trucks 19+ do not have vacuum power brakes anymore. They did away with the vacuum pump as well. All the braking is controlled electronically by a unit low on the drivers side firewall. Here is what you have in your truck now. https://gmauthority.com/blog/2018/10/zf-highlights-brake-by-wire-system-in-silverado-sierra/

Edited July 1, 2020 by 2016 Sierra Owner
added web link.

Sierra20-20 · July 1, 2020

That’s good info, seems like they could replace that and likely it would fix the issue .. it’s in the shop as we speak getting worked on hopefully. I recorded and showed them the noise..I’ll keep you Guys posted on the outcome. I’m hoping they figure it out.. the pedal feeling and noise is coming straight from behind the pedal so based on your placement knowledge, would make sense if it’s defective or failed

Sierra20-20 · July 10, 2020

Any new info on the AC strange noises? I’m trying to accept that it’s normal noises but I’m having a hard time lol.. as for the brakes, they found an update and calibrated it (via computer) and haven’t felt the vibration or sound since.. I wonder if there’s just a noisy AC compressor that they began using or different fan or something? Seems like I haven’t read any similar issues other than 2019 or 2020 ?? The dealership said it was normal AC noise again.. ?? I dunno

Freddie Franklin · July 22, 2020

I'm having the same issue with my '20 trailboss. Truck is at the dealership for the whistle for the 4th time so they said it's been escalated to engineering. The first 3 times they said "unable to replicate". I hear my whistle soon as I crack a window/sunroof at 60+ and considerably louder when setting hvac to recirculation. Theyve had the truck for almost 2 weeks now so hopefully I'll have an update soon.

Dhxrris · July 22, 2020

33 minutes ago, Freddie Franklin said:

I'm having the same issue with my '20 trailboss. Truck is at the dealership for the whistle for the 4th time so they said it's been escalated to engineering. The first 3 times they said "unable to replicate". I hear my whistle soon as I crack a window/sunroof at 60+ and considerably louder when setting hvac to recirculation. Theyve had the truck for almost 2 weeks now so hopefully I'll have an update soon.

Let us know. Btw I have done a bit of tests on my own. Take the bottom glove box off, then remove cover for cabin filter . After that remove the filter. Inside is the recirculate door. I have had my wife drive while I press up on the door and it stops. Anyhow I have scheduled service next Tuesday with a gm engineer. Lemme know what that say.

ps if your in North Carolina , Alabama , Canada reach out to these guys. They work for the dealers and specialize in fixing leaks . The owner that is in Canada states he knows exactly what the problem is and will talk with the tech or advisor : last two dealerships I went to wouldnt speak with him. Don’t know why but ..... they wouldn’t .

https://www.leakpro.com/

Sad Colorado · August 2, 2021

I bought a 2020 Colorado 11 months ago and have had to deal with this noise from day one. 10k miles on it and is now louder.

With the AC off it makes a whistle when the fan is on 3 or 4. The Dealer claims that the MFG says its "normal". I doubt that upper mgt would think so if they had to drive one.