Headlamp range adjustment (HRA) headlamp function - GF82.10-P-1001R

MODEL 230 except CODE (487) Active Body Control (ABC) 

Function requirements 

• Circuit 15 ON
• Low beam ON

Function 

The headlamp range adjustment (HRA) is prescribed by law to prevent xenon headlamps dazzling oncoming traffic. The HRA automatically maintains the inclination angle of the headlamps within the legally defined limits regardless of the vehicle load.

Headlamp range changes, which are brought about by acceleration or deceleration, are also compensated for.

To achieve this, the required values of the left front level sensor (B22/8) and left rear level sensor (B22/7) are read in by the xenon headlamp control unit (E1n1) directly, processed and forwarded via the headlamp range adjustment bus (HRA bus) to the xenon headlamp control unit (E2n1).

The xenon headlamp control unit (E1n1) at the left front lamp unit (E1) actuates the left headlamp range adjustment motor (E1m1). The xenon headlamp control unit (E2n1) at the right front lamp unit (E2) actuates the right headlamp range adjustment motor (E2m1).

The xenon headlamp control unit (E1n1) and the xenon headlamp control unit (E2n1) operate as a master/slave combination: The xenon headlamp control unit (E1n1) is the master unit, which receives the corresponding signals, evaluates them and passes them on to the slave unit, the xenon headlamp control unit(E2n1).