ABS pump starts when stopping

I have a 99 Sierra 4wd. My ABS keeps actuating at about 6 mph. I bought a new bearing assy about 3 months ago from the dealer because the bearings were shot. There are also new rotors and brakes installed within the last 8 months. The problem started before just before the bearing was installed but was not consistant. I have tested the ohms of the sensors and the reading is equal on both wheels. 1.037. I have had a computer plugged into the truck and went for a ride all sensors appear to be working correctly(mph). The computer showed the system activating when the brake light came on, and at 6 mph the ABS pump started but the computer said the pump did NOT start. It appears the new sensors that are part of the Bearing assy are epoxied in place, if that is true there is no adjustment that I can see. Could it be a relay stuck in a closed position? Any help would be greatly appreciated. Kaloma

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//2000CAYukon