Headlights, Tail Lights and Car Lighting

Complete assemblies or bulbs: what are you replacing?

A complete assembly replaces the whole housing, such as a pair of projector headlights or a set of tail lights, and is listed by make, model and year. A bulb replaces only the light source and is found by base code in the manual. LED bulbs placed in a halogen reflector housing can scatter light and dazzle other drivers, while projector housings usually control the beam better. Fitment types include direct fit, vehicle specific and universal.

Voltage, color temperature and electrical quirks

Cars use 12 volts and some trucks 24, so listings quoting 12-24 V suit both. A color temperature of 6000K gives a cool white; lower figures look warmer and yellower, which many drivers find easier in rain and fog. Kelvin describes color, not brightness. LEDs draw little current, so a car may flag a bulb failure or flash fast, which resistors or a decoder fix. Check the markings your region requires, such as DOT, SAE or E-mark.

Questions about Headlights, Tail Lights and Car Lighting

Why do my LED turn signals flash fast?

LEDs draw less current than filament bulbs, so the flasher relay thinks a bulb has failed. Load resistors or an LED-compatible flasher relay bring the normal rate back. Some modern cars need a CAN bus decoder instead.

Does a higher Kelvin number mean a brighter light?

No. Kelvin describes color temperature. Brightness is measured in lumens, and the beam pattern matters more than either for seeing the road. A bluer light is not necessarily better.

Are headlight assemblies sold as pairs?

Many are sold as a set of two, left and right, but some are single units. Read the title for set of 2 or the side noted, and confirm the year range and projector or reflector type.