The tail light on most E90 BMW 3 Series models uses standard 12-volt bulbs. In typical halogen configurations, the tail/brake function shares a dual-filament bulb, while separate bulbs handle the turn signal and reverse lights. There are variations by year, market, and trim, and some later models use LED tail lights instead of bulbs.
The E90 tail light assembly commonly relies on a few specific bulb types: a dual-filament bulb for tail and brake, an amber bulb for the turn signal, and a separate bulb for the reverse light. Models with LED tail lights will differ, so always verify against your exact build and model year.
Bulb types by function
Below are the typical bulbs used in the E90 tail-light clusters, depending on function. Variants exist by year and market.
Tail and brake light
The tail and brake functions are usually served by a single dual-filament bulb, providing both the dim tail light and brighter brake glow.
- P21/5W dual-filament bulb (commonly with a BA15d base) for tail and brake functions.
Conclusion: One bulb handles both tail and braking, using two filaments to switch between brightness levels.
Turn signal
The turn indicator in the E90 tail light is typically an amber bulb with a single wattage that flashes to signal turns.
- PY21W or WY21W amber turn signal bulb (21W).
Conclusion: The turn signal is a separate bulb from the tail/brake, and is color-coded amber in most configurations.
Reverse light
Reverse illumination in the E90 tail light assembly is normally provided by a dedicated bulb separate from the tail/brake and turn signal.
- W16W wedge-base bulb for the reverse light.
Conclusion: The reverse light uses a distinct bulb, not shared with tail/brake or turn signal functions.
Notes on compatibility and variants
Because the E90 range spans several years and markets, some models may differ. Some early or market-specific versions used different bulb codes or, in some trim lines, LED tail lights that do not use replaceable bulbs. Always check the owner's manual, the service booklet, or remove the taillight cover to confirm the exact bulb type for your vehicle.
Summary
In the typical halogen E90 tail-light setup, expect a P21/5W dual-filament bulb for tail and brake, a PY21W (or WY21W) amber bulb for the turn signal, and a W16W wedge-base bulb for the reverse light. LED variants will differ and may not use these bulb types. When replacing bulbs, verify the specific configuration for your model year and market.