W21/5W T20 W3x16q Canbus 24 SMD automotive bulb 12V/24V white universal

Automotive W21/5W T20 W3x16q Canbus 24 SMD bulb is a universal dual-filament replacement for signal and brake light sockets requiring a W3x16q base. Designed to operate on both 12V and 24V electrical systems, this white light bulb integrates Canbus support to minimise false error messages on vehicles with sensitive onboard electronics. The compact T20 form factor and multiple SMD diodes deliver a bright, consistent white light suitable for rear signalling and stop lamp functions.

Advantages

This W21/5W T20 bulb provides a direct-fit solution for dual-filament applications without the need for additional resistors in most modern vehicles thanks to built-in Canbus compatibility. The use of multiple SMD LEDs ensures even light distribution and stable luminous output over time, while the universal W3x16q base allows straightforward installation in cars, trucks and trailers. The bulb’s compatibility with both 12V and 24V systems makes it versatile across a wide range of vehicles.

Suitable for

• Replacement of W21/5W dual-filament signal and brake bulbs in passenger cars
• Commercial vehicles and trucks that use 24V electrical systems
• Trailers and caravans requiring a universal T20 W3x16q lamp
• Vehicles with Canbus or modern electronic monitoring systems to reduce dashboard errors

Key specifications

• Base type: W3x16q (T20)
• Filament configuration: dual-filament equivalent for signal and brake functions
• Light colour: white
• LED type: 24 SMD diodes
• Operating voltage: compatible with 12V and 24V systems
• Form factor: T20 compact bulb

How to use

Switch off the vehicle ignition and allow the lamp assembly to cool before beginning. Remove the lamp housing or access cover according to the vehicle manufacturer’s instructions, then extract the existing W21/5W W3x16q bulb by careful twisting and pulling. Align the W3x16q base of the replacement LED bulb with the socket and insert it until it seats securely. Refit the housing and test the signal and brake functions to ensure correct operation. If necessary, consult the vehicle manual for specific removal and installation steps.

Usage recommendations

For reliable operation, verify compatibility with your vehicle’s lamp assembly and electronic system prior to installation. In some older systems or in installations with light monitoring that still report errors, an additional CANbus adapter or load resistor may be required. Avoid exposing the bulb to direct high-pressure water jets and ensure connections are secure and corrosion-free.