The Volvo 740 brake light uses a P21/5W bulb size for the rear lighting system. Data for the specified component covers the range from 1985 through 1992.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Volvo 740 uses the P21/5W bulb for brake lighting across the 1985-1992 model years.
The P21/5W is a dual-filament bulb operating at 12V, rated at 21W for the primary filament and 5W for the secondary filament, and it follows the ECE signalling standard used in Europe and worldwide markets.
The P21/5W uses a BAY15d bayonet base, which is an offset twin-pin fitting designed to prevent incorrect installation by ensuring the bulb can only be seated in one orientation.
The center high mount stop light on the Volvo 740 uses the P21W bulb, which is specified for the 1988-1992 model years.
The P21W is a single-filament bulb operating at 12V with a 21W rating, also conforming to the ECE standard.
Unlike the P21/5W, the P21W uses a BA15s bayonet base, which is a single-pin fitting. The two bulb types are not interchangeable due to their differing base configurations.
Although both the P21/5W and P21W share a 21W primary filament rating and the same ECE standard, their base types and filament counts differ, making cross-substitution between brake and center high mount stop light positions incompatible.