Harley-Davidson FXDC Super Glide Custom Turn Signal Bulb Size

Harley-Davidson FXDC Super Glide Custom rear turn signal bulb uses a P21W size. The replacement chart covers 2007 to 2014 vehicle 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.

Rear Turn Signal

Years	Bulb Size
2007-2014	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 specified rear turn signal bulb for the Harley-Davidson FXDC Super Glide Custom across the 2007-2014 model years.
The P21W operates on 12 volts and draws 21 watts, which places it in the standard wattage range for single-filament automotive signalling applications.
As a single-filament bulb, the P21W is dedicated solely to one lighting function, distinguishing it from dual-filament types that serve two functions from a single housing.
The P21W uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width. This base type requires a socket designed specifically for single-contact bayonet fitment and is not interchangeable with double-contact BA15d sockets.
The P21W is rated under ECE standards, a regulatory framework used across Europe and numerous other markets worldwide, which governs output and performance tolerances for signalling bulbs.