Pull the sliding-door panels and check for power at both sides of each lock actuator with a test light while someone holds the lock button. If power is present but the locks do not move, replace the door lock actuators. Tapping an actuator may free it temporarily, but replacement is the lasting repair.
The owner of a 1999 Pontiac Transport/Montana reported that both sliding-door locks did not respond to the remote or door lock buttons. The expert suggested listening for the actuators and, if they click without moving, replacing them. The owner heard no sound, and one door later began working on its own. The expert then advised checking for power at the actuators and noted that tapping them can temporarily restore operation before replacement.
