Polaris Frontier Classic Brake Bulb Size

The Polaris Frontier Classic brake uses bulb size 3157 and bulb size 921 for the lighting system. Data for the specific bulbs covers the range from 2003 to 2004.

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
2004	3157 (With Adjustable Seat)
2004	921 (With Fixed Seat)
2003	921

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921

Other Locations

Additional Notes

The 3157 is a dual-filament wedge bulb classified under the T25 body type, operating at 12V with a wattage split of 27W for the high-intensity filament and 7W for the low-intensity filament. This dual-filament design allows a single bulb to serve both brake and running light functions simultaneously.
The 921 is a single-filament wedge bulb classified under the T15 body type, operating at 12V at 16W. Unlike the 3157, it carries only one filament, meaning it performs a single lighting function rather than two.
Both the 3157 and 921 conform to ANSI standards recognized in the United States and Canada, placing them within a standardized sizing and performance framework common across North American automotive applications.
The 2004 Polaris Frontier Classic uses different brake bulb sizes depending on seat configuration. Units fitted with an adjustable seat take the 3157, while units fitted with a fixed seat take the 921.
The 3157 and 921 are not interchangeable. Beyond their different wattage ratings and filament counts, the T25 and T15 wedge bases are physically distinct sizes, so substitution between the two is not possible without modification.
The 2003 Polaris Frontier Classic specifies the 921 across its brake bulb application, with no seat-configuration distinction recorded for that year.