Harley-Davidson FXSTC Softail Custom Turn Signal Bulb Size

Harley-Davidson FXSTC Softail Custom front turn signal bulbs use 198 size, while rear turn signal bulbs use P21W or 199 size. The replacement chart covers 1993 to 1999 model 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.

Front Turn Signal

Years	Bulb Type	Shop
1993-1999	198	Check Price

Rear Turn Signal

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
1994-1999	1156	P21W	Check Price
1993	199	199	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 2W.	198	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W	Check Price
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156	Check Price
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	199	Check Price

Other Locations

Additional Notes

The front turn signal positions on the Harley-Davidson FXSTC Softail Custom use the 198 bulb across the 1993-1999 model years. This bulb follows the ANSI standard applicable in the US and Canada and is a T5 miniature wedge type rated at 12V and 2W.
The T5 designation refers to the tubular glass envelope, which is approximately 5/8 of an inch wide. The wedge base means the bulb is held in its socket by the glass envelope itself rather than a separate metal base, making it a tool-free press-fit installation.
The rear turn signal position uses the P21W bulb for the 1994-1999 model years. The P21W follows the ECE standard used in Europe and worldwide, features a BA15s single-contact bayonet base, and is rated at 12V and 21W.
The 1993 rear turn signal position uses the 199 bulb instead of the P21W. The 199 is an ANSI-standard single-filament bulb that also uses a BA15s bayonet base and shares the same 12V, 21W electrical rating as the P21W.
Although the 199 and P21W share the same BA15s base type and identical voltage and wattage ratings, they belong to different standards regimes. The 199 is classified under ANSI as a variant of the 1156 bulb family, while the P21W is an ECE-classified type. These standards differences can affect physical tolerances and interchangeability.
The front 198 bulb at 2W and the rear P21W or 199 bulbs at 21W represent a significant power difference between the front and rear turn signal circuits on this model, a factor relevant when assessing load compatibility with aftermarket flasher relays.