Abstract: Method and device for controlling an auxiliary unit (10) in a motor vehicle by means of a device consisting of a control unit (40) and a switch (30) for switching the auxiliary unit on and off. To ensure the maintenance of an auxiliary unit of this type and to prolong its life using simple means, it is proposed, among other things, that the control unit (40) will repeatedly signal actions to be taken to a driver of the vehicle or directly to the switch. A first action is the switch-on of the switched-off auxiliary unit (10) at a specific point in time if it (the unit) has been switched off for a long period of at least some weeks. A second, succeeding action is the switch-off of the unit (10) switched on in the manner described, after a short period of at least some minutes.