It could be something stuck in between your brake pad and rotor. Sometimes rocks and thingscan flick up in there and it grinds against your rotor when you put on the brakes.
A vibrating brake pedal is an indication of a warped rotor. Noise is common to disk brakes but depending on the noise it can mean that the brake pads are worn out and you are due for a brake job.
brake switch located on the top of the brake pedal
you most likely have low brake fluid or if it stops fine its just an annoying noise
If you are not losing brake fluid I would say the master cylinder is bad. Can you tell what direction the occasional noise is coming from?
Do you mean when you push the pedal " hard " you hear noise..........if so could be the ABS..........if not, then please have your brakes checked for safety.
Should be located at the upper end of brake pedal
Brake booster problem?
If you mean the switch that puts the brake lights on and off when you step on the brake pedal then it's located where the brake pedal is, can't miss it.
If you follow the brake pedal up under the dash, you'll see the switch where the actuator arm from the brake master cylinder attaches to the pedal.
Sounds like the power brake booster is bad. Get it checked out.
do your brake lights work wen pressing brake . if not its the brake pedal sensor
Check on the upper end of brake pedal (under dash)