Rolls-Royce Silver Wraith II Turn Signal Bulb Size
The Rolls-Royce Silver Wraith II uses P21W and 1159 bulb sizes for both front and rear turn signal applications. Replacement chart data covers 1977 to 1980 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W bulb is the most frequently specified type across the Rolls-Royce Silver Wraith II turn signal positions, appearing in both front and rear applications for the 1977-1978 and 1980 model years.
P21W is an ECE-standard single-filament signalling bulb rated at 12V and 21W, fitted with a BA15s bayonet base. Its single filament means it serves one lighting function only, which aligns with its dedicated turn signal role.
The BA15s bayonet base on the P21W features a single locating pin on its collar, which locks the bulb into the socket at a fixed rotational position.
The 1159 bulb is specified for both the front and rear turn signals on the 1979 Rolls-Royce Silver Wraith II, making 1979 the sole model year in these specifications to use this bulb type.
The 1159 is an ANSI-standard dual-filament bulb operating at 12V, fitted with a BAY15d bayonet base. Its dual-filament construction means it is capable of serving two separate lighting functions within a single housing.
The BAY15d base on the 1159 bulb uses two offset pins, which physically prevents it from being inserted into a BA15s socket. This makes the P21W and the 1159 mechanically incompatible with each other's sockets despite both using bayonet-style bases.
Because the P21W and 1159 use different base types and standards, the 1979 Silver Wraith II requires different replacement bulbs than the 1977-1978 and 1980 model years, even though all four years share the same front and rear turn signal positions.
The ECE standard governing the P21W originates from European and worldwide regulatory frameworks, while the ANSI standard governing the 1159 applies to North American markets, reflecting a distinction in regional automotive lighting specifications.