Two problems related to brake antilock control unit/module have been reported for the 1999 Chevrolet C1500. The most recently reported issues are listed below.
Antilock brakes wants to engage at low speeds.
Abs motor control unit failure, after seeing many complaints on the web I am reporting it here. Abs warning light came on and pump motor started running. Even when turning off the motor, the unit still runs. Abs failure. Had to pull fuse to stop, now driving without abs and abs and brake warning lights are on. $1000 - $1500 to repair problem, will most likely drive without abs for a long time.