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2017 Chevrolet Malibu - Buzzes loudly

I have a 2017 Malibu LT. I bought it new and it now has about 10,000 miles. It occasionally makes a loud buzzing sound which seems to be coming from under the dashboard. This noise started soon after I bought the car. It sometimes occurs when driving and can be quite a distraction. It usually happens when I pull into the garage and turn off the ignition. Turning off the radio has no effect. Opening the car door does not stop it. Putting my foot on the brake and the noise ceases, remove my foot and the sound resumes. I have just had to leave the car with the noise continuing. It eventually will stop. What is the connection with the brake and some other electronic activity?

My local Chevrolet dealer cannot resolve this problem. In their defense, it has never made the noise when it has been in their shop.

Did you drive around with the one of their employees in the car?

You could try pulling fuses one by one to see if the noise is coming from something electrical on one of those circuits.

No. But Ii could not make the noise happen if I wanted to. It is intermittent

where are the fuses?

The next time the buzzing starts, open the hood and place your hand on the vacuum brake booster to and feel if the buzzing is from that.

I don’t know if the brake booster has the vacuum check valve or if it’s located at the vacuum pump at the front of the engine.

But since the buzzing is effected by the operation of the brake pedal, that’s where I’d start.

Tester

Will the buzzing happen if you switch between normal and recirculate modes on the air inlet? What about if you change modes between floor, vent and defrost output?

Have not tried that. will do next time.

Thanks

What does the brake booster look like ?

The ABS system will open and closed valves rapidly and the sound is noticeable. It shouldn’t happen except when the car is first started and those moments when the ABS or ESC system is active.

It’s the big round thing on the firewall.

https://www.carid.com/cardone/power-brake-booster-mpn-54-71537.html?singleid=2114307000&url=92380748

Tester

Good ideas above. Could also be an under-dash relay associated with the stop light circuitry that’s doing it.

It never happens on startup

The fuses are where your owner manual shows them to be located.

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