LED Headlight Conversion Kit (H4 / H7 / H11)

What to Check When Sourcing

LED headlight conversions are one of the highest-volume automotive aftermarket categories from China, and also one of the highest for false specifications and safety violations. The E-Mark certification question is critical for EU market legality.

E-Mark certification. In the EU, replacement vehicle headlight bulbs must be E-Mark approved (ECE Regulation 37/99/112) to be road-legal. Many LED conversion kits are sold CE-marked but without E-Mark, meaning they are legal to manufacture and sell but technically illegal to use on public roads in EU countries. If your buyers are European, specify E-Mark R112 approval. This significantly limits your factory options but protects your customers from fines.

EMC compliance for CanBus vehicles. LED drivers generate switching noise that triggers CanBus “bulb failure” warnings on modern vehicles. A CanBus decoder (load resistor + capacitor) suppresses this on most vehicles, but not all. Test with the 10 most common vehicle platforms in your target market before committing.

Projector vs. reflector housing compatibility. LED chips have a different light source geometry than halogen filaments. In reflector housings, the LED geometry matters enormously for beam pattern — a misplaced LED chip produces glare that blinds oncoming drivers. Request a beam pattern test photo on the specific housing type your market uses.

Common Issues

Thermal management in enclosed headlight housings — Some original equipment headlight housings are sealed; LED conversion kits designed for vented housings overheat in sealed applications. Verify the operating temperature spec and test in an enclosed housing for 2 hours.

Claimed lumen output — 10,000lm per pair claims are common; actual measured output is typically 6,000–7,500lm for a $15 kit. Test with an integrating sphere and document actual output before acceptance.