All Doors Fail To Lock From One Switch

Lower driver's window. Operate power door lock switch or door cylinder lock switch to lock position. If door will not lock using power door lock switch, replace power door lock switch. See POWER DOOR LOCK SWITCH  under REMOVAL & INSTALLATION. If door will not lock using door cylinder lock switch, replace door cylinder lock switch. See DOOR CYLINDER LOCK SWITCH  under REMOVAL & INSTALLATION. If door will lock using power door lock switch and door cylinder lock switch, problem is intermittent. Visually inspect and wiggle test related wiring.