Ski-Doo MX Z 600 X Brake Bulb Size

Additional Notes

• The 1157 is the dominant brake bulb type across the Ski-Doo MX Z 600 X, appearing in nine of the ten model years covered, specifically 2001-2006 and 2008-2010.
• The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W/5W output, where the higher wattage filament serves the brake function and the lower wattage filament serves a secondary lighting function.
• The BAY15d bayonet base features two offset pins, a design that prevents incorrect installation by ensuring the bulb can only be seated in one orientation.
• The 2007 Ski-Doo MX Z 600 X departs from the surrounding model years by specifying a 921 bulb rather than the 1157.
• The 921 is a single-filament wedge-type bulb in a T15 form factor, rated at 12V and 16W, and it uses no base pins, instead relying on the tension of the socket contacts to hold it in place.
• Because the 1157 uses a BAY15d bayonet base and the 921 uses a wedge base, the two bulb types are not physically interchangeable despite sharing the same 12V operating voltage.
• Both the 1157 and 921 are classified under ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances for each type.
• The filament count also differs between the two types, as the 1157 carries dual filaments while the 921 carries a single filament, meaning they serve different circuit configurations and cannot substitute for one another functionally.