Volvo 940 front side marker bulbs use 1034NA or 1157NA sizes, while rear side marker bulbs require P21/5W bulb sizes. The replacement chart covers 1991 to 1993 vehicle 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 front side marker bulb for the Volvo 940 changed from the 1157NA to the 1034NA between the 1992 and 1993 model years.
The 1034NA is a variant of the 1157NA, both sharing the same BAY15d bayonet base, 12V rating, and 21W/5W dual-filament configuration.
The primary distinction between the 1034NA and 1157NA is that the 1034NA features natural amber glass, whereas the 1157NA produces white light through clear glass. Both carry the NA suffix designation in these specifications, indicating natural amber glass on both types listed here.
The 1157NA and 1034NA are both governed by ANSI standards, applicable to the United States and Canada markets.
The rear side marker position uses the P21/5W across the 1991-1993 model years.
The P21/5W follows ECE standards, which are used in European and worldwide markets, in contrast to the ANSI-standard bulbs specified for the front position.
Despite the regulatory difference between the front and rear bulbs, all three bulb types share the BAY15d bayonet base and an identical 12V, 21W/5W electrical rating, meaning they are electrically equivalent.
The BAY15d base is an offset dual-pin bayonet fitting, a design that physically prevents incorrect single-filament bulbs from being seated in a dual-filament socket.
Although the 1034NA and P21/5W share the same base type and wattage, substituting one for the other across front and rear positions would involve crossing between ANSI and ECE standards, which carry different glass and construction specifications.