Harley-Davidson XL1200C Sportster 1200 Custom Brake Bulb Size

The Harley-Davidson XL1200C Sportster 1200 Custom uses a 3157 bulb size for brake applications. The replacement chart covers 2005 to 2009 model years with corresponding bulb size specifications.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2005-2009	3157

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157

Other Locations

Additional Notes

The 3157 is the brake bulb size specified for the Harley-Davidson XL1200C Sportster 1200 Custom across the 2005-2009 model years.
The 3157 is an ANSI-standardized bulb type, meaning its physical and electrical specifications are governed by a recognized North American standard used in both the United States and Canada.
This bulb follows the T25 wedge form factor, a designation that describes its tulip-shaped glass envelope and the wedge-style base, which seats directly into a socket without a separate metal base or bayonet pins.
The 3157 operates on a 12-volt electrical system, consistent with the standard automotive and motorcycle electrical architecture found in this application.
As a dual-filament bulb, the 3157 contains two separate filaments within a single envelope, rated at 27 watts and 7 watts respectively, allowing it to serve both a higher-intensity brake function and a lower-intensity running light function from one unit.
The 3157 designation is not interchangeable with single-filament variants such as the 3156, which shares the same T25 wedge base but lacks the second filament required for dual-function operation in this fitment.