Kawasaki KAF620 Mule 4010 4x4 Brake Bulb Size

Additional Notes

• The P21/5W is the brake bulb type specified for the Kawasaki KAF620 Mule 4010 4x4 across the 2015-2022 model years covered in these specifications.
• The P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single envelope. The higher-output filament operates at 21 watts for the brake or turn signal function, while the lower-output filament operates at 5 watts for a secondary function such as a running or position light.
• The P21/5W operates on a 12-volt electrical system, which is consistent with standard automotive and utility vehicle electrical architecture.
• This bulb type uses a BAY15d bayonet base. The BAY15d designation indicates an offset dual-contact base, where the two pins are positioned at different heights along the base. This offset pin arrangement is a deliberate anti-misalignment feature that prevents the bulb from being inserted in the wrong orientation, which would otherwise reverse the two filament circuits.
• The P21/5W is governed by ECE (Economic Commission for Europe) standards and is used across European and worldwide markets. It is not an SAE-standard bulb type, which is the system more commonly associated with North American vehicle specifications.
• Because the BAY15d base uses offset pins, it is not interchangeable with the BAY15s base, which is a single-filament bayonet fitting with symmetrically placed pins. Substituting a single-filament BAY15s bulb would result in an incorrect fitment regardless of wattage.