Harley-Davidson FLD Switchback Turn Signal Bulb Size

Harley-Davidson FLD Switchback rear turn signal bulbs utilize a 199 and P21W size. The replacement chart covers 2012 to 2016 vehicle production 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.

Rear Turn Signal

Years	Bulb Size
2016	199
2013-2015	P21W
2012	199

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	199
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The rear turn signal on the Harley-Davidson FLD Switchback uses two distinct bulb standards across its production years: the 199 and the P21W.
Both the 199 and P21W share identical electrical ratings of 12V and 21W, and both use a BA15s single-contact bayonet base with a single filament.
The 199 is an ANSI-standard bulb used in the United States and Canada, while the P21W follows the ECE standard applied in Europe and other international markets.
The 199 is a variant of the 1156 bulb type, meaning it shares the same base configuration and general construction as that widely used automotive signalling bulb.
For the Harley-Davidson FLD Switchback, the 199 bulb is specified for the 2012 and 2016 model years, whereas the P21W is specified for 2013-2015.
Despite their different regional standards and designations, the shared BA15s base means the 199 and P21W are physically interchangeable in terms of socket fitment, though regional compliance requirements may differ.