One problem related to brake sensor has been reported for the 1999 Chevrolet C/k Pickups. The most recently reported issues are listed below.
Loss of breaking below 5 mph. Anti lock brakes quit working. Coming to a stop, at about 5 mph, brake pedal pushes back against foot, all breaking ceases and howling or burrrrr noise is heard. If you force the brake pedal down as in panic stop, pedal goes almost to floor and braking resumes. If you let up on the brake pedal and reapply pressure, breaking returns to normal operation. This is an intermittent problem, but repeatable. There are no warning lights on the dash. The gm dealer says my vehicle is not involved in the abs recall as it is in minnesota. Dealer says I have to will probably have to replace the hubs and sensors to fix problem. They are aware of the problems with the brakes, but at this time, they say it is my responsibility as the recall does not affect my vehicle.