2004 Ford Explorer ABS light

Unfortunately, most of the time an ABS light indicates an electricat concern, not a mechanical concern. The concern is more than likely the sensor located on the rear differential housing. My guess is if you had it scanned on a computer, you would get codes for the left and right REAR sensors. Most of them do not have individual sensors for left and right rear, but one sensor in the housing. Change that sensor and you should resolve the concern.