See more and see better – a complete guide to selecting and replacing used LED and Xenon headlights

A functioning lighting system is the foundation of active safety, determining the driver's reaction time after dark and in difficult weather conditions. Replacing a damaged headlight with a brand new one at an authorized service center often costs several thousand zlotys, prompting many users to seek alternatives. Cheap replacements, while tempting, rarely offer the correct beam geometry and durability of electronic systems, often yellowing after just one year of use. A compromise solution that combines original quality with a reasonable price is used automotive lighting from a dismantled vehicle, provided it comes from a reliable source. Global Parts offers verified headlights and lamps that maintain the manufacturer's homologation parameters. However, the correct selection of technology – whether classic xenon or modern LED – requires knowledge of specific markings and control module compatibility.

Xenon technology – diagnostics and typical system faults

Gas discharge lamps, commonly known as xenon lamps, generate light through an electric arc in an atmosphere of noble gases, requiring a complex high-voltage power supply. Over time, the light color shifts toward purple, which is the first sign of filament wear and the need to replace them in pairs to maintain consistent road illumination. In older models, such as the now-classic xenon systems of the BMW E36 (often retrofitted) or E46, the problem can be caused by burnt-out lens reflectors, which prevent even a new filament from providing sufficient light. Diagnosing a xenon fault is not always straightforward, as flickering or failure of the lamp can result from both a faulty bulb and control gear.

BMW E60 and E87 Xenon converter – the heart of the high-voltage system

The voltage converter is a key component, responsible for igniting the gas in the filament and maintaining a stable arc, and its failure is often mistaken for filament burnout. Moisture entering the lamp through leaky covers is the main enemy of electronics; for example, the BMW E87 xenon ballast mounted under the headlight is particularly vulnerable to water runoff from the wheel arch. In the BMW E60, the xenon ballast (often from Valeo or Hella) also controls the leveling and steering functions, so its failure generates errors on the dashboard and locks the lens in the service position. Choosing a used, original ballast is safer than installing a Chinese replacement, which often interferes with the CB radio and audio system .

Types of bulbs – BMW E60 Xenon D1S or D2S?

Correct filament selection is fundamental to headlight operation, as individual types differ in the igniter mounting method. Newer models, such as the BMW E60 (LCI facelift versions) and the Audi A6 C6, feature the D1S system as standard, with the igniter integrated into the filament base, eliminating voltage losses in the wiring. Older systems used D2S filaments with a separate igniter mounted at the rear of the headlight, which could lead to high-voltage breakdowns. In the case of the phrase " BMW E60 Xenon D1S, " it's worth remembering that installing a filament with a color temperature other than the factory 4300K (white-yellow) or 6000K (cool white) can impair visibility in the rain.

LED headlight and electronics – precision and service challenges

Lighting based on light-emitting diodes (LEDs) offers lightning-fast response times and a color similar to daylight, but is virtually indispensable. An LED headlight is essentially an advanced computer with its own cooling system (heat sinks, fans), where damage to one section of the diodes often necessitates replacement of the entire headlight. In modern cars, the BMW LED system (e.g., Adaptive LED in the F and G series) works with a windshield camera to dynamically cut sections of the light beam to avoid blinding other drivers. Purchasing a used LED headlight requires a thorough inspection of the lens' condition and, most importantly, checking for welds on the mounting brackets, which could affect the beam geometry.

BMW X3 E83 LED tail light – control board problem

LED rear lights are also prone to failure, and faults often involve cold solder joints on printed circuit boards (PCBs) inside the lamp. A known problem with the BMW X3 E83 LED rear lights is that the position lights begin to flicker or go out completely, even though the diodes themselves are working. Replacing the entire lamp with a used original from Global Parts is often a quicker and more durable solution than attempting to solder burnt VALEO control unit traces, which oxidize over time. Similar problems affect turn signal modules in newer Audi models, where moisture causes corrosion of the contacts.

Additional lighting – third brake light Mercedes W203

Signaling components must meet stringent brightness standards, and their failure is a sure fail on the MOT. The Mercedes W203 third brake light (station wagon and sedan) often cracks with age or leaks, leading to trunk flooding and short circuits in the electrical system. Replacing this component with a used original guarantees a perfect fit to the trunk lid curve, something often lacking in cheap replacements. When selecting small LED components, such as license plate or marker lights, always verify the plug type, as manufacturers may change them during the model year.

Compatibility and Coding – Turn Module and Adaptation

Physically fitting the headlight into the mounting holes is only half the battle, as modern lighting requires "presenting" it to the car's computer. Replacing a Xenon headlight (AHL/AFS) in a BMW or Audi requires relocating the control modules from the old headlight or coding new ones if they were replaced. It's common for the same car model (e.g., a BMW E60) to have three different headlight types: halogen, standard xenon, and dynamic xenon – the connectors may look identical, but the pinout differs. Verifying the VIN or comparing the OEM numbers on the old part's label is the only way to avoid costly mistakes.

Table 1: Comparison of headlight technologies in used cars

Characteristic	Xenon / Bi-Xenon	LED (Full LED / Matrix)
Light source	Replaceable filament (D1S, D2S, etc.)	Integrated diodes (non-replaceable)
Vitality	approx. 2000 - 3000 hours	Theoretically lifetime (actually dependent on electronics)
Light color	4300K - 6000K (changes over time)	5500K - 6000K (constant)
Typical faults	Burnt out filament, flooded converter, dull reflector	Controller damage, diode section burnout, fan
Repair cost	Medium (parts can be replaced)	High (often replacing the entire lamp)

Critical lighting elements in popular models

Car model	Problematic element	Symptoms of failure
BMW E60 / E61	Xenon converter	Lamp goes out, flashes, no leveling (flooded).
BMW X3 E83	LED tail light (in fender)	"Dead" LED strips, burnt out bulb errors.
Mercedes W203	Third brake light	Cracks in the plastic, leaks, some of the diodes do not light up.
Audi A6 C6	LED rear lamp	Weak light (ground), burnt out brake diodes.
BMW E87 / E90	Turning Module (AHL)	Flashing green diode on the light switch, lamps squinting.

FAQ – Frequently asked questions about used lighting

Question	Global Parts Expert Answer
Can I install LED headlights in a car that had regular bulbs?	This is called a retrofit. Physically possible, but legally and technically complex. It requires replacing the wiring harness and headlight module, adding a self-leveling system and washers (for headlights >2000 lm), and coding. Without homologation, the car loses its registration certificate.
How to recognize a lamp from the English version (RHD)?	The lamp's lens or housing has approval markings (arrows). Right-hand traffic lights (LHD - Europe) have a right-hand arrow or no arrow. English-style lights have left-hand arrows or asymmetrical markings. Additionally, the "English" light shines higher on the left side.
What is the difference between D1S and D2S filament?	The D1S has an integrated igniter (the silver cube at the base), which is a newer design. The D2S is a burner-only design that requires an external igniter that fits onto the back of the bulb. They are not interchangeable.
Why does the xenon lamp glow a different color after replacing it?	A new xenon bulb needs about 100 hours of operation to "light up" and achieve the target color. Furthermore, the old bulb in the second lamp may have already changed color due to age. Therefore, xenon bulbs are always replaced in pairs.
Does fogging headlights mean they are damaged?	Light fogging in the lower corners, which disappears when the lights are turned on, is a physical phenomenon (temperature difference). However, large drops of water or standing water inside the lamp indicate a leak (glue leak, cracked housing, missing cover) and require attention.