Buzzing noise with engine off in ignition mode?

(Posting this here as well as the 3rd gen forum trying to figure out what this noise is)

I noticed a strange, continuous buzzing noise when in ignition / accessory mode (two start button presses without your foot on the brake). No fan or anything else electrical on in the cabin.

I’ve been searching to see what this might be and I found the below YouTube video that demonstrates what I’m hearing (noise at the beginning is the brake booster, it’s the “electrical transformer” noise afterwards):



I recently swapped my speakers out with some components up front and they seem more sensitive to whatever this electrical noise is, and it can be heard through them when the car is in ignition mode or with the engine running.

 

Here’s a video with the noise from my truck (may need to turn volume up):

 

Dealer replied back and said they weren't sure, "it's normal" ... any ideas?

 

Hi Were you able to find reason for this buzzing noise. I have Toyota Rav4 2011 and I am having same issue. Just asking if you were able to find the source or root cause of this noise.

 

Vacuum pump failure?

 

check this video youtu.be/CM-j5ye0TSo
doesn't seem like pump failure car is running alright

 

Normal sound, my 2019 makes the same noise on accessory power. I heard it through my aftermarket speakers that used passive crossovers - I had the crossovers sitting behind the front kick panels near the existing wires and the crossovers acted like microphones, causing the hum to come through the speakers.