Polaris Trail Brake Bulb Size

The Polaris Trail brake utilizes 921 and 90 bulb sizes for the lighting components. Data for the provided specifications covers the period from 1985 through 1999.

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
1993-1999	921
1985-1992	90

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 13W.	90

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Additional Notes

The Polaris Trail uses two distinct brake bulb types across its model years: the 921 and the 90, both of which conform to ANSI standards recognized in the United States and Canada.
The 921 is a T15 wedge-style bulb rated at 12 volts and 16 watts. Its wedge base design means it is held in place by friction within the socket rather than by a locking bayonet mechanism.
The 90 is a single-filament bulb fitted with a BA15s bayonet base, rated at 12 volts and 13 watts. The BA15s designation indicates a single-contact bayonet cap with a 15mm base width.
The Polaris Trail (1993-1999) uses the 921 bulb for the brake light position.
The 90 bulb applies to the 1985-1992 model years.
The two bulb types are not interchangeable. The 921 uses a wedge base while the 90 uses a BA15s bayonet base, making the socket fitment physically incompatible between the two groups.
The wattage difference between the two bulbs is 3 watts, with the 921 drawing slightly more power than the 90 at the same 12-volt operating voltage.
1992 represents the final model year specified with the 90 bulb, and 1993 represents the first year specified with the 921, marking the point at which the brake bulb type changed.