Polaris Trail Touring Brake Bulb Size

Additional Notes

• The Polaris Trail Touring uses two distinct brake bulb types across its model years: the 3157 and the 921, both of which conform to ANSI standards recognized in the United States and Canada.
• The 3157 is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a wattage split of 27W for the high-intensity filament and 7W for the low-intensity filament, a configuration that supports both brake and running light functions within a single housing.
• The 921 is a single-filament wedge bulb in the T15 form factor, rated at 12V and 16W, making it a simpler and lower-output unit compared to the 3157.
• The Polaris Trail Touring (2004-2006) and the 2010 model year share the 3157 bulb specification for the brake light position.
• Model years 1996-2000 and 2002-2003 of the Trail Touring use the 921 bulb in the brake light position.
• The T25 and T15 designations refer to the outer envelope size of each bulb, with T25 being physically larger than T15; the two types are not interchangeable despite sharing the same wedge base style.
• The dual-filament design of the 3157 distinguishes it functionally from the single-filament 921, meaning a direct substitution between the two would not replicate the original electrical behavior of the brake light circuit.
• Both bulb types operate on a 12V electrical system, which is consistent with standard automotive and powersports vehicle architecture.