Mandatory control of the lighting system (Audi A4 B6)

Check the headlight adjustment regularly. In addition, the vehicle's lighting devices should be checked before each trip.

To do this, turn on the ignition and turn on the parking, low beam, high beam and fog lights one by one. In the rear of the car, the rear lights, license plate lights, reversing lights and rear fog lights must function perfectly. You should always take a small supply of the most essential lamps and lights with you on a trip. The lamps are marked on the base or glass bulb.

A vehicle with halogen headlights should have a supply of the following bulbs:

Incandescent lamp	Lamp type	Power
High beam	H7	55 W
Low beam	H7	55 W
Parking light	Glass base	5 W
Flashing light	Bayonet socket	21 W (orange)
Brake light/rear light	Bayonet socket	21/5 W
Reversing lights	Bayonet socket	21 W
Rear fog light	Bayonet socket	21 W
License plate light	Spotlight lamp	5 W
Upper brake light	LEDs
Ceiling lamps	Spotlight lamp	10 W
In the case of headlights with gas discharge lamps, it is additionally necessary to have a gas discharge lamp:
Gas discharge lamp	D2S	35 W

Adjusting the headlight angle

In Germany, headlight range adjustment is required by law for new cars. This adjustment is intended to prevent oncoming drivers from being dazzled when the vehicle is loaded. In the Audi A4, the headlight range is adjusted electrically. For this purpose, each headlight has a servomotor, which is controlled by manually or automatically activating the regulator (automatic control for gas discharge lamps is mandatory). The servomotor is removed separately from the headlight.

Xenon light

In headlights with gas-discharge lamps, xenon technology allows achieving very bright ("daytime") light. Compared to a halogen lamp, the luminous flux increases two and a half times, and energy consumption decreases by 35 percent. The road is illuminated better, the range of the headlight increases.

Instead of an incandescent lamp, a gas discharge lamp is used in headlights with gas discharge lamps. When arc ignition voltage is applied, (from 10 to 21 kV) a gas mixture consisting of xenon and metal halides becomes conductive. This creates an electric arc. By applying a controlled 400 Hz alternating current, the metal filler evaporates and emits light. An electronic control unit is required to turn on and operate the xenon lamp.

Due to the strong light in cars with xenon lamps, there must be automatic headlight leveling. The replacement of lamps must be carried out by a qualified person, since when working with a high-voltage unit (as when working with the ignition system) under certain circumstances, life-threatening conditions may arise.