Harley-Davidson XL883L SuperLow Turn Signal Bulb Size

The Harley-Davidson XL883L SuperLow rear turn signal uses a P21W bulb size for optimal lighting performance. A replacement chart covering 2011 to 2019 model years documents the bulb specifications across this production range.

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

Rear Turn Signal

Years	Bulb Size
2011-2019	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The P21W is the sole rear turn signal bulb type listed for the Harley-Davidson XL883L SuperLow across the 2011-2019 model years.
The P21W operates at 12 volts with a 21-watt output, classifying it as a single-filament incandescent bulb intended for signalling functions.
This bulb follows the ECE (Economic Commission for Europe) standard, a regulatory framework adopted across Europe and numerous other markets worldwide.
The P21W uses a BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm collar width, distinguishing it from dual-contact variants such as the BAY15d.
The single-filament construction of the P21W means it serves one dedicated function, in this case turn signalling, rather than combining multiple lighting roles within one bulb.
Because the BA15s base is a single-contact type, substitution with physically similar but electrically different bayonet bases would result in incorrect fitment for the XL883L SuperLow rear turn signal position.