XC90 AWD L6-3.2L VIN 98 B6324S (2007)
Headlamp Control Module: Description and Operation
Design
Design
Left headlight control unit (LHCU) / right headlight control unit (RHCU)
The left headlight control unit (LHCU) / right headlight control unit (RHCU) are located within the headlights.
The left headlight control unit (LHCU) / right headlight control unit (RHCU) handle the active regulation of the light beam. Active regulation means that
the light beam is turned out to the left or right. The light beam is turned out at different amounts and different rates depending on vehicle speed and
steering wheel angle.
Information is transferred between the left headlight control unit (LHCU), right headlight control unit (RHCU) and headlight control module (HCM) via
LIN communication.
The lamp housing contains a sensor that indicates whether the light beam has been turned out to the right or left. The left headlight control unit (LHCU)
and right headlight control unit (RHCU) send this information to the headlight control module (HCM).
If there is no communication with the headlight control module (HCM) or a fault arises in the left headlight control unit and/or the right headlight control
unit (RHCU), active regulation ceases. If this is the case, the headlights are aimed straight ahead.
The left headlight control unit (LHCU) and right headlight control unit (RHCU) can be diagnosed.
