'04 Ranger braking sound question

My husband has a 2004 Ford Ranger 4x4, about 80,000 miles on it. He kept hearing noise when he braked, and the brake pedal would vibrate upon stopping. He thought at first it was the brakes needing to be replaced, or bad rotors. He replaced all of the brakes and both front rotors.
I just drove the truck, and can confirm it's acting, well, wonky. The sound doesn't appear to be coming from the tire areas, but rather from under the hood, towards the left side of the engine compartment. And the vibrating upon braking doesn't happen when you first apply the brakes, it happens as the truck is almost stopped. You can feel the vibration in the brake pedal as the noise occurs, which kind of sounds like a whining sound, not rubbing. And the truck does stop, but as the pedal vibrates, it feels like it takes longer to stop like it should, almost like how you skid the last few inches when braking on ice, but it's clear, dry road.
I am stumped, and can't find anything anywhere specific to this situation. Does anyone have any ideas?

Sounds like ABS is malfunctioning.

Agreed- ABS is engaging at near zero speed - most likely due to wheel speed sensors ring corrosion. My yukon tries to engage ABS at about 4 mph or less- and the speed sensors read bad- The only way to replace corroded ring is to replace wheel bearing assembly- and is not worth it to me. I unplugged ABS fuse- now have normal braking with no noises- but do have ABS light on on dash.

You can test yours by pulling ABS fuse and see if noise subsides- at least yoou'll know what it is.