Abstract: A lock system is provided for vehicles and the like of the type having at least one closure. A lock housing is mounted adjacent the closure, and includes a lock barrel with an axial tumbler groove, a positioner shoulder adjacent an outer portion of the barrel and a keeper shoulder adjacent an inner portion of the barrel. A lock plug is closely received in the barrel for rotation between locked and unlocked positions, and includes a keyway and outwardly biased, radially shifting tumblers. A control key is inserted into the keyway to retract all of the tumblers except a positioner tumbler that engages the positioner shoulder to locate the lock plug in a first axial position in the barrel. When the control key is removed, an outer keeper tumbler is biased outwardly for abutting contact with the keeper shoulder. A dealer key is inserted into the keyway to retract all of the tumblers except the positioner and outer keeper tumblers to permit rotation of the plug between the locked and unlocked positions.