Patent ID: 6525478
Filing Date: 2003-02-25
Classification: B60Q

Abstract:
A device for checking an evaluation circuit for automatic switching operations of illumination devices in vehicles, comprising:an evaluation circuit designed using analog technology; and a sensor unit including a global sensor for detecting light conditions in the environment of the vehicle and a directional sensor for the directed detection of the light conditions in the direction of travel in front of the vehicle, the sensor unit outputting signals to the evaluation circuit in order to establish whether a change in the switching state of the illumination devices is required; wherein, in an operating state, a voltage supplied to the sensor unit is briefly interrupted at predetermined intervals, as a result of which a â€œnightâ€  condition is simulated, the voltage supply interruptions being detected by the evaluation circuit when the evaluation circuit is functioning correctly, wherein, when the evaluation circuit is not functioning correctly, a signal is generated directing attention to the faulty functioning and causing further steps to be initiated.