Roof rack for a motor vehicle, method for operating a control unit of a motor vehicle and corresponding control device

The roof rack assembly (1) has roof rails (2) constructed to be fastened on a vehicle roof of the motor vehicle. A load carrier constructed to be installed on the roof rails. The load carrier has a mounting projection engaged with the roof rails through the recess (7) when the load carrier is installed and cooperating with a mounting receptacle (6) for retaining the load carrier. A cover (9) closing the recess when the load carrier is not installed, and a detection device (18) detecting a cover state of the recess. An independent claim is included for a method of operating a controller of a motor vehicle.