Ski-Doo Summit 800 Hill Climb Tail Light Bulb Size

The Ski-Doo Summit 800 Hill Climb tail light requires a P21/5W bulb size for proper operation. Available data for the specified component covers the range from 2009 to 2010.

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
2009-2010	P21/5W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W

Other Locations

Additional Notes

The P21/5W is the tail light bulb type specified for the Ski-Doo Summit 800 Hill Climb across the 2009-2010 model years.
The P21/5W is a dual-filament bulb, meaning it carries two separate filaments within a single glass envelope. The higher 21W filament typically serves the brake light function, while the lower 5W filament handles the running light function.
The P21/5W operates on a 12V electrical system, which is standard for powersports vehicles in this category.
The bulb uses a BAY15d bayonet base. The offset pins on this base are positioned at different heights, which prevents the bulb from being seated in the wrong orientation and ensures the correct filament aligns with each circuit.
The P21/5W is governed by ECE regulations, a standard recognized across Europe and numerous other markets worldwide. This regulatory origin is relevant to fitment, as ECE-rated bulbs are subject to specific output and performance requirements.
The BAY15d base is not interchangeable with the similarly named BA15d or BA15s bases. The BAY15d features offset indexing pins, whereas BA15d has level pins and BA15s is a single-filament base, making substitution between these types incompatible with the Summit 800 Hill Climb socket.