Abstract: A circuit arrangement for indicator lights in motor vehicles comprises four differently dimmable groups of lights I for tachometer and speedometer illumination 1, 2, II for the remaining dashboard illumination 3, 4, III for the center panel and foot space illumination 5, 6, and IV for the illuminating lights 7, 8 in a radio unit. These lights can be connected to a voltage source via a potentiometer 9 and an electronic amplifier 12. The amplifier has a number of different characteristic curves, corresponding to the number of groups of lights. The shape of these curves is such that, when the potentiometer 9 is turned from its null position into its end position, at first only the voltage for the first group of lights I, that is for the speedometer and tachometer illumination 1 and 2, is increased from zero to a average value. The remaining groups are switched on sequentially.

Abstract: A cooling system for a water-cooled vehicle engine has a radiator through which cooling water flows and which can be exposed to cooling air by an electric fan (9). A first heat sensor (F1) on the engine block senses the water outflow temperature, while a second heat sensor (F2) senses the radiator outflow temperature. The sensed values from both sensors are fed to an electronic control unit (11) which also stores temperature threshold values for both sensor, at which certain functions have to be performed. In the event of failure of either sensor, the electronic control unit (11) takes over the function of the sensor: from the temperature value sensed by the other sensor a temperature equivalent value is formed by adding or subtracting the temperature difference which exists between the two sensors at running temperature. The control unit then activates the appropriate function if the relevant threshold value is reached or exceeded.

Abstract: In a switching device for the interior lighting L of a motor vehicle, having a timing element R1 C1 which is controlled by a gate contact switch TK which is opened by closing a vehicle door and which sets on the interior lighting during a certain time lapse after closing the door, a second timing element R2 C2 is provided to be controlled by the closing of the gate contact switch TK and to set off the interior lighting L after a predetermined time interval, when the ignition switch ZS is open. Thereby, the discharge of the vehicle battery is prevented due to the interior lighting L when a door remains inadvertently open, but, when the ignition is turned on, the interior lighting L remains on if a door is open.

Abstract: This invention pertains to a circuit for controlling an electric device in a motor vehicle such as a light. The circuit has a control switch, a door switch and a semiconductor switch. The control switch activates the device either directly, or through the door and semiconductor switches. The control switch also has a neutral position in which the device is deactivated and the semiconductor switch is off reducing the current drain of the device on the motor vehicle battery.

Abstract: An electrical circuit is presented for operating a motor vehicle window, wherein the drive motor (M1 and M2) can be switched on by means of an operating switch (S1 and S2), even after the turning off the ignition (opening the ignition switch ZS) and after opening a vehicle door (closing of the door contact switch TK) or alternatively by opening a vehicle door or by the opening and reclosing of a motor vehicle door. The circuit is so designed that only a small operating current flows therethrough when the ignition is turned on as well as when the door is open, as long as the operating switch is not actuated, thus preventing a discharging of the battery even if the motor vehicle door is left open for a longer period of time.