Description
Auxbeam B21-PRO 3157 White/Amber Switchback LED Bulbs – 4-Pack
This T25/3157 dual-colour switchback set is the 4-bulb package without an added C8 decoder option. It is designed for combined parking/daytime running light and turn-signal applications with the correct 3157 socket and wiring.
Lighting Functions
- Cool white light for the parking light or daytime running light function, where supported by the original wiring.
- Amber flashing light for the turn signal function.
- White-to-amber switching works only where the original bulb provides both functions.
Selected Package and Manufacturer Information
- Package selection: 4 × B21-PRO T25/3157 white/amber LED bulbs; no C8 decoder option selected.
- Auxbeam specifies SMD 3030 LED chips and fan cooling for the B21-PRO switchback range.
- Auxbeam lists 6500 K white and 3000 K amber and a nominal 4,000 lm per two bulbs for the base product.
Electrical specification and supply
Auxbeam specifies 5 W white / 25 W amber per bulb and a 12–24 V electrical range while stating use in 12 V cars. This listing is for compatible 12 V applications; 24 V vehicle suitability is not confirmed.
Ordered from the supplier; not held in our own stock. Auxbeam listed this exact four-bulb variant as available on 7 November 2026. Availability and dispatch timing may change. Contact us for the current delivery estimate before ordering; no guaranteed delivery date is stated.
Fitment and Road-Use Notes
Check the original bulb designation and whether the vehicle uses a standard 3157 or CK-type socket; these pin arrangements are not interchangeable. Additional load resistors or decoders may be necessary to address hyperflash or dashboard warnings. Compatibility and error-free operation are not guaranteed. European E-mark approval has not been verified.


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