I just bought a used 2012 Prius with 75000 miles on it. I keep hearing his humming noise on the driver side. It is electronic noise not a mechanical. If anyone can help that will be great. Attached a YouTube video. It does do it on the beginning of the videos and it is an intermittent noise. f
It could be the brake booster pump. It will usually run firsr thing in the morning as you enter the car and again each time the brake is used. A failing brake booster may cycle frequently but is hard to hear while moving.
