The adjustment of the headlamp light beam according to the load is carried out by means of a special device (located inside the front light cluster) which tilts it appropriately, lowering the light beam if the vehicle is heavily laden and raising it if the load lessens.The adjustment device is managed by the headlamp alignment control unit which requires:
a speedometer signal, used by the control unit to ascertain the vehicle status (stationary or moving) and for its own internal strategies;
a dipped headlamps on signal (either operated manually via the steering column switch unit or automatically through the dusk sensor) as a result of which the control unit enables the function; See E2011 DIPPED HEADLAMPS
a signal coming, respectively, from the two potentiometers present on the two vehicle axles (front and rear) used by the control unit for determining the correction of the headlamp alignment to be implemented depending on the load.
Once these signals have been acquired, the headlamp alignment control unit activates the two stepping motors inside the headlamps, always taking into account the position they are in.The headlamp alignment control unit has its own diagnostic signal. See E8010 DIAGNOSTIC MULTIPLE CONNECTORA possible control unit failure state is signalled by the instrument panel by means of a special message on the display.