Control And Monitoring Of The Headlights And Bulbs
WARNING: This page does not describe the selected car, but rather 37 other vehicles, including the 2006 BMW 330Ci, 2006 BMW 325Ci, 2005 BMW M3, 2005 BMW 330xi, and 2005 BMW 330i. However, it is still accessible from the selected car via links, so may be relevant.
All lighting loads are actuated and individually diagnosed via the light switch cluster.
- Output limitation: If the on-board supply voltage exceeds a coded value, the lights are dimmed to increase the service life of the bulbs. A separate value is coded for each type of bulb (rear lights, brake lights, etc.). These values are coded during assembly, at the end of the production line.
- Reduced ON current: The light switch cluster switches on the individual lights one at a time to prevent the vehicle electrical system from being overloaded unnecessarily by voltage peaks and high currents produced when the lights are switched on.
- Prevents light intensity fluctuations: Valvetronic creates short load peaks resulting in voltage dips in the vehicle electrical system. These voltage dips can cause fluctuations in the intensity of the vehicle lighting. Corresponding parameters are stored in the light switch cluster to prevent visible light intensity fluctuations as much as possible.
- Cold monitoring: For cold monitoring, the lights are switched on briefly without the bulbs glowing (thermal inertia of bulb elements). LEDs and D2-S bulbs (= xenon lights) are not cold-monitored (LEDs respond too quickly; D2-S bulbs must never be actuated by voltage pulses). Cold monitoring takes place when terminal 15 is switched ON. This pre-drive-check indicates the condition of the lights before the start of a journey (Check Control car symbol). Cold monitoring detects either "light available" or "open circuit". The cold current is a multiple of the rated current.
- Hot monitoring: The rated current of bulb when it is switched on is monitored via the status output of the lamp driver. Within 2 seconds, a defective bulb can be recognised (frequency counters count the frequency of a recognised defect; the defect is reported when a certain number is reached). When the ignition is switched off, all frequency counters are reset to zero to prevent a bulb that has already been replaced from being reported as being defective again.