This Underground Lighting collection focuses exclusively on the PY24W bulb, an OEM automotive signalling bulb commonly used as a front turn signal or daytime running light (DRL) in vehicles from BMW, Audi, GM, and select Japanese manufacturers. The PY24W format is defined by its WX3x16d plastic base with offset keyed tabs, ensuring correct alignment and preventing installation into incompatible sockets such as P24W, 7440, or 3157.
The category centres on the PY24W LED replacement bulb, which upgrades the original 24W halogen PY24W filament bulb to a solid-state LED light source and operates on standard 12V automotive electrical systems and is installed using a plug-and-turn twist-lock mechanism. Because LED bulbs draw less current than halogen bulbs, many vehicles detect them as failed bulbs, causing hyperflash or bulb-out warnings. To maintain proper blink rate and CANbus stability, PY24W LED systems may require integrated decoders or external load resistors (~6–8 ohm), depending on vehicle BCM sensitivity.
The PY24W bulb supports two primary functions:
- Front Turn Signal (Amber Output)
Produces an amber signalling light with rapid illumination. LED upgrades improve daytime visibility and response time.
- Daytime Running Light (White Output)
Some vehicles wire PY24W as a constant-on DRL. White LED versions, such as Plasma White (≈6000K), provide a clean daylight appearance when used in clear housings.
Our collection currently features the PY24W Plasma White LED (650 lumens) designed for turn signal and DRL circuits. With approximately 650 lumens of directional output when paired with the CANbus correct resistor/decoder, it exceeds typical halogen visibility while remaining compatible with reflector housings and lens-filtered assemblies. In amber-lens housings, white PY24W LEDs produce legal amber output through filtering; in clear housings, amber LED variants are required to maintain DOT/ECE color compliance.
Housing compatibility is typically open reflector bowls or lens-filtered signal housings, where the LED emitter must replicate the original filament position to maintain uniform illumination and avoid hotspots. White LEDs rely on lens filtering, while clear-lens housings require amber LED output for legal turn-signal compliance.
Still not convinced why to upgrade to this PY24W LED turn signal ? In simple terms, it supports OEM halogen replacement and LED signalling upgrades through Underground Lighting, focusing on fitment-specific design, CANbus stability, and improved signalling performance.
Explore our curated LED & HID conversion kits, bulb & ballast collections for auxiliary lights, LED strobes & switchback turn signal lights, and conveniently check vehicle compatibility with our easy-to-use Bulb Finder.
