Headlamp (headlights) for your car

To see and to be seen with the headlight

The headlight is a strong lamp on the front of a car. It has a signalling function, enabling the driver to see the road in front of him in the dark. The initially used carbide lamps have over time developed to a real high-tech product with several modules and functions.

Headlight components

A headlight consists of the following components:

• Light source for driving light/dipped beam
• Light source for main beam
• Reflector
• Housing
• Cover (in modern cars up to 10 years)
• Levelling unit
• Optional: washer system (except xenon headlights, where it is mandatory)

As a light source, three different systems are used for headlights:

• Filament lamps
• Xenon
• LED

Filament lamps are standard since several decennia. They are cheap in production and easy to replace. Their lighting performance has improved over the years. Filament lamps (incandescent lamps) have a limited life span and a low efficiency rate. A considerable amount of the energy is lost via heat radiation. Xenon headlight are very strong, however expensive and their construction is complicated. Xenon headlights also have a limited life span and should always be replaced in pairs, which makes the repair of the light unit to a considerable cost factor. LED headlights are not widely spread as yet. In signalling systems they gradually become standard. For their use as active driving light, their performance has been considered too weak until recently. The appropriate lamps are quite expensive, although a drop in prices can be noticed. The first LED lamps which can be replaced by the traditional filament lamps are available. LED lights have a higher efficiency and life span than average lamps. Reflector, housing and especially the cover are often exposed to wear. Penetrating moist blinds the reflector. UV radiation from the sun and grinding sand particles may cause the headlight cover to become dull over time. The housing can break at its mounting through vibrations of the engine. This damage can be partly repaired, e.g. by careful polishing of the headlight cover. If a housing breaks or a reflector is fully blinded, replacement is the only option. The headlight levelling system is a separate module, operated by a small electric motor in most cars. Older cars like for example the Fiat Cinquecento or Volvo have a hydraulic headlight levelling system. These are very susceptible to wear and expensive in repair. Many cars have been scrapped prematurely when this module failed. The headlight cleaning system is mandatory for xenon headlights. In other cars it is optional. It consists of a small spray nozzle, generally connected to the windscreen washer. The washing systems of the 80ies with separate small wipers are no longer in use today.

Defects of the headlights

Headlight defects are generally caused by the lamps. As a rule, the filament lamps can be replaced in a few minutes without any tools. Today, this is not necessarily the case. Furthermore, headlights can fail through the following causes: penetrating water, blinded reflectors and covers or fractured housings. Also, headlights are first affected in case of collisions. They are always replaced on occasion of accident repair.

Buying a new headlight

The price of a new headlight greatly depends on its construction and the car type. For cheap compact cars, prices of a new front headlight start under 50 EUR (c. £45). Complex xenon headlight can easily cost several hundred until over a thousand euros per piece. Discounts and special promotions can help to save money. Comparing prices is therefore always worthwhile. You should however always check the branded quality. Only original certified parts offer the desired performance.