Harley-Davidson FLHTCUL Electra Glide Ultra Classic Low Tail Light Bulb Size

Harley-Davidson FLHTCUL Electra Glide Ultra Classic Low tail light uses a 3157 bulb size. The replacement chart covers 2015 to 2016 production 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
2015-2016	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 an ANSI-standardized bulb type recognized across the United States and Canada, establishing a consistent technical baseline for the specification.
The Harley-Davidson FLHTCUL Electra Glide Ultra Classic Low uses the 3157 bulb size for the tail light position across the 2015-2016 model years.
The 3157 follows the T25 wedge form factor, a designation that refers to the shape and base style of the bulb housing.
As a dual-filament bulb, the 3157 operates two separate filaments within a single unit, allowing it to serve both a lower-intensity running light function at 7W and a higher-intensity braking function at 27W.
The bulb operates at 12 volts, consistent with the standard electrical system voltage found in most production motorcycles.
Because the 3157 carries two filaments with different wattage ratings, substituting a single-filament bulb of similar size would result in the loss of one lighting function at this position.