ok rear hatch on 98 ford explorer is making a buzzing sound. i believe it to be lock actuator. i can see it but it looks fine. just making buzzing sound and not locking of unlocking the door.any tips on replacing it. also my drivers side door. if the door is open, i can put the key in the door and lock and unlock the door with the key and the switch. when door is closed i cannot lock or unlock the door with the key or the switch. it wont turn to unlock the door. any ideas on the drivers side door???