Harley-Davidson FXDC Super Glide Custom Tail Light Bulb Size

The Harley-Davidson FXDC Super Glide Custom tail light uses a 3157 bulb size for rear illumination. The replacement chart covers 2007 to 2014 model years with corresponding bulb 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
2007-2014	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 sole tail light bulb type listed across all model years covered in these specifications, spanning 2007-2014 for the Harley-Davidson FXDC Super Glide Custom.
The 3157 is an ANSI-standardized bulb type recognized in both the United States and Canada, meaning its physical and electrical characteristics conform to a defined industry specification rather than a proprietary format.
This bulb follows the T25 wedge form factor, a designation that refers to its base style and body shape, which determines physical fitment within the socket.
The 3157 operates on a 12-volt system, consistent with the standard electrical architecture found in most production motorcycles.
A defining characteristic of the 3157 is its dual-filament construction, which allows it to serve two distinct brightness levels from a single bulb. The higher 27W filament typically corresponds to the brake light function, while the lower 7W filament serves the running light function.
Because the 3157 carries two filaments, substituting it with a single-filament alternative would result in the loss of one lighting function, making filament count a critical factor in replacement compatibility.