Ski-Doo Expedition Sport ACE 900 Brake Bulb Size

The Ski-Doo Expedition Sport ACE 900 brake component utilizes a P21/5W bulb size for the lighting system. Data for the specified equipment covers the range from 2014 to 2018.

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
2014-2018	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 brake bulb type specified for the Ski-Doo Expedition Sport ACE 900 across the 2014-2018 model years.
P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single glass envelope. The higher-output filament operates at 21 watts for the brake or stop function, while the lower-output filament operates at 5 watts for a secondary function such as tail or running light.
The bulb operates on a 12-volt electrical system, which is standard for most powersport and automotive applications.
P21/5W uses a BAY15d bayonet base. The BAY15d designation indicates an offset dual-contact base, where the two pins are positioned at different heights to prevent incorrect installation orientation.
The P21/5W designation follows ECE (Economic Commission for Europe) standards, reflecting a specification recognized across European and worldwide markets rather than the SAE standards more common in North American automotive contexts.
Because the BAY15d base is offset, it is not interchangeable with the BA15d base, which shares a similar bayonet form but features pins at equal heights. Substituting a BA15d bulb in a BAY15d socket is not possible without modification.