The power door lock actuators may become slow to operate or stop working completely and require replacement.Google+
Car Problem Reports
Chevrolet Suburban 2500 Power Door Lock Actuators May Fail
Chevrolet Suburban 2500 Problem
Average Mileage: 89,000 mi (78,000 mi - 100,000 mi)
Visitor, 1999 Chevrolet Suburban 2500, 100,000 mi
2 passenger door locks and the rear door lock all failed.