It is provided a fixture for mounting a window lifter assembly in a vehicle door, wherein the fixture can be mounted in a vehicle door and at least includes at least one mounting portion, via which the window lifter assembly can be mounted on the fixture in a plurality of mounting positions, and at least one tool interface, via which a tool adapted for connection can reversibly be connected to the fixture, wherein the window lifter assembly properly mounted on the fixture can be shifted from one of the mounting positions into another one of the mounting positions by a torque introduced into the connected tool. adjusting