Mitsubishi Mirage G4 Tail Light Bulb Size

Additional Notes

• The two bulb types found in the Mitsubishi Mirage G4 tail light specifications are the P21W and the P21/5W, both governed by ECE standards recognized across Europe and worldwide.
• The P21W is a single-filament signalling bulb operating at 12V and 21W, fitted with a BA15s bayonet base. The single filament means it serves one lighting function, typically a turn signal or a dedicated brake light.
• The P21/5W is a dual-filament signalling bulb operating at 12V with two wattage ratings, 21W and 5W, fitted with a BAY15d bayonet base. The two filaments allow one bulb to serve two separate lighting functions, such as a combined tail and brake light.
• The BA15s base of the P21W and the BAY15d base of the P21/5W are not interchangeable. The BAY15d base features two offset pins to prevent incorrect installation, while the BA15s base carries a single locating pin.
• The Mitsubishi Mirage G4 (2017-2020) uses the P21/5W across those model years, indicating a consistent dual-filament fitment requirement for that period.
• The 2023 Mirage G4 specifies the P21W rather than the P21/5W, which reflects a shift to a single-filament bulb and a different base type for that model year.
• Because the P21W and P21/5W share the same 21W rating at their primary filament but differ in base design and filament count, substituting one for the other is not supported by the specifications.