Active Headlamps (Vehicles With Active Headlamps Only)
Active headlights are an intelligent headlight system that optimizes lighting of the road surface at night by expanding the light beam. The motorized headlights are controlled by the headlamp control module (HCM), which retrieves signals from the CAN network and from directly connected sensors.
For the active headlight function to be enabled, the headlamp control module (HCM) (4/114) requires information on the following: vehicle speed, current gear, light conditions and steering angle.
The headlight control module (HCM) receives information from the following control modules:
- Brake control module (BCM) (4/16) for information on vehicle speed
- Transmission control module (TCM) (4/28) for information on current gear (automatic transmission)
- Central electronic module (CEM) (4/56) for information from the reversing light switch (3/10) (manual transmission)
- Central electronic module (CEM) (4/56) for information from the twilight sensor (7/12)
- Steering wheel module (SWM), (3/254), information about steering angle
The active headlamp function is only enabled if the following conditions are met:
- The vehicle must be in motion, that is, travel at a speed faster than 4 km/h.
- Reverse gear must not be engaged.
- No daylight light conditions.
In addition, active headlights have to be activated via Light switch module (LSM) (3/111).
When the function is active then Headlamp Control Module (HCM) receives continuous information about the vehicle's speed and steering angle. The vehicle's speed comes from Brake control module (BCM) and information about steering angle from Steering wheel module (SWM).
Using this information, the Headlamp Control Module (HCM) calculates current expansion of the light pattern.