Operator control system for a vehicle, having - an operator control unit which is arranged in a fixed manner in the vehicle, by means of which at least one first function of the vehicle can be operated, - a device (29, 30) necessary for executing the first function, - an interface via which a mobile operator control unit can be coupled to the vehicle, wherein at least one second function of the vehicle can be operated with the mobile operator control unit that cannot be operated by the operator control unit which is arranged in a fixed manner in the vehicle, - a device (31, 32) necessary for executing the second function, and - a control device which controls the first function of the vehicle depending on user inputs to the operator control unit arranged in a fixed manner in the vehicle, and which enables operation of the second function if the mobile operator control unit is coupled to the vehicle via the interface, wherein the second function can be controlled depending on user inputs to the mobile operator control unit, - wherein the device (31, 32) necessary for executing the second function can only be activated in such a way that it executes the second function if the mobile operator control unit is coupled to the vehicle, characterized in that - the second function is a subfunction of the first function, and - the first function is an climate control function, wherein the device necessary for executing the climate control function comprises a blower which controls the degree of ventilation, heaters for the air in the interior of the vehicle or for the air supplied to the interior of the vehicle, and/or window defoggers, and the second function is a seat heating function, wherein the device necessary for executing the seat heating function is a seat heater integrated into the seats. - an operator control unit which is arranged in a fixed manner in the vehicle, by means of which at least one first function of the vehicle can be operated, - a device (29, 30) necessary for executing the first function, - an interface via which a mobile operator control unit can be coupled to the vehicle, wherein at least one second function of the vehicle can be operated with the mobile operator control unit that cannot be operated by the operator control unit which is arranged in a fixed manner in the vehicle, - a device (31, 32) necessary for executing the second function, and - a control device which controls the first function of the vehicle depending on user inputs to the operator control unit arranged in a fixed manner in the vehicle, and which enables operation of the second function if the mobile operator control unit is coupled to the vehicle via the interface, wherein the second function can be controlled depending on user inputs to the mobile operator control unit, - wherein the device (31, 32) necessary for executing the second function can only be activated in such a way that it executes the second function if the mobile operator control unit is coupled to the vehicle, characterized in that - the second function is a subfunction of the first function, and - the first function is an climate control function, wherein the device necessary for executing the climate control function comprises a blower which controls the degree of ventilation, heaters for the air in the interior of the vehicle or for the air supplied to the interior of the vehicle, and/or window defoggers, and the second function is a seat heating function, wherein the device necessary for executing the seat heating function is a seat heater integrated into the seats.