Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Exterior Lighting: Functions: Overview
The functions of the exterior lighting are integrated in the footwell module.
These lighting functions are:
- Side lights
- Low beam headlight
- High-beam headlight
- Headlight flasher
- Fog light
- Direction indicator light
- Hazard warning light
- Tail light/license plate light
- Dynamic brake light
- Reversing light
- Parking lights
- Welcome light
- Delayed switch-off home lights
- Daytime driving light.
The headlight lighting functions are powered via a headlight driver module or the footwell module.
The footwell module controls a constant brightness level for each headlight. This is achieved with a pulse-width regulated voltage supply. Voltage fluctuations in the vehicle electrical and bus systems are compensated for by the pulse width.
The headlight driver module receives the information on the voltage supply for its light source via the LIN bus.
In addition to the standard light functions, further functions for the exterior lighting are integrated in the footwell module:
- Dynamic beam throw adjustment system
- Lamp monitoring
- Cold monitoring with lights "OFF"
- Hot monitoring with lights "ON"
- Visual alarm/feedback
- Central locking system
- Antitheft alarm system
- Crash signal
- Special case at "Terminal 15 OFF"
- Emergency operating mode
- Adaptive headlight with
- Turning lights
- Adaptive headlight-range adjustment system.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.