Ski-Doo Summit 600 Brake Bulb Size

Additional Notes

• The 1157 is the more widely used brake bulb across the Ski-Doo Summit 600 model range, appearing in nine of the twelve model years covered by the specifications, spanning 1999-2006 and 2010.
• The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output, meaning it operates one filament for running light functions and a second, brighter filament for braking signals.
• The 1157 uses a BAY15d bayonet base, a two-pin offset base design that prevents incorrect installation by ensuring the bulb can only be seated in one orientation.
• The 921 is a single-filament wedge-type bulb in the T15 form factor, rated at 12V and 16W, and it does not use a bayonet base, relying instead on spring tension within the socket for retention.
• The Ski-Doo Summit 600 used the 921 bulb exclusively during the 2007-2009 model years, representing a departure from the 1157 fitment used in surrounding years.
• The 1157 and 921 are not interchangeable. They differ in base type, filament count, wattage, and physical form factor, meaning a socket designed for one will not correctly accept the other.
• Both the 1157 and 921 are ANSI-standardized bulbs recognized in the United States and Canada, meaning their electrical and physical specifications are consistent across manufacturers producing bulbs under those designations.
• The wattage difference between the two bulb types is notable: the 1157 draws up to 21W on its primary filament, while the 921 draws 16W, reflecting a lower power output for the single-filament design.