You are probably hearing the fuel pump, this is normal.
Humming noise on the front passenger side of a 1997 Ford Explorer XLT may be due to a bad tire. Try to jack up the tire and spin it by hand to see if the noise is there.
It will most likely be the wheel bearing
Is the humming noise happening all the time the brakes are applied? Does it change pitch as the car slows? Is it loudest just before stopping?
wheel bearing
possibly your running RCAs on the same side as your power cable
Loose Lug nuts bad control arm...
To the drivers side.
Most commonly this is a tire wear issue
Remove the inside door panel of your Chevy Cavalier. Remove the drivers side mirror wiring harness, if the mirror is electric. Remove the drivers side mirror retaining bolts. Reverse the process to install the new drivers side mirror.
i changed my left side bearing then after 3 months there was a humming on the left side so i took it to the shop they said it was the right i said the left so they did the right and found out it was the left so both wear done now there's still a humming noise what do i do now.
on the firewall on the drivers side and also on the front door post on the drivers side.
2nd one on drivers side