Abs Brakes Functioning Always

[SlimJim26]

I have a 2000 Jimmy, and my ABS brakes function during every stop, just as it is almost stopped, the motor kicks in and the pedal is pushed back at me, kind of leaving me with no brakes until I pump them. I recently replaced the brake controller and I replaced all the calipers, and bled the system, but it still does it. I cleaned the front sensors, but don't know where the rear one is. Any ideas on a solution would be much appreciated.