The Volvo 940 front turn signal requires a 1157NA or 1034NA bulb size, while the rear turn signal uses a P21W or P21/5W bulb size. The replacement chart covers 1991 to 1993 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The front turn signal positions on the Volvo 940 use dual-filament bulbs across all three listed model years, while the rear turn signal position shifts from dual-filament to single-filament between 1991 and 1992.
The 1157NA and 1034NA bulbs are both ANSI-standard types rated at 12V with a 21W/5W dual-filament configuration and share the same BAY15d bayonet base, making the 1034NA a variant of the 1157 family.
The front turn signal on the 1993 Volvo 940 uses the 1157NA, while the 1991-1992 model years use the 1034NA, indicating a bulb type change at that model year boundary despite both types sharing the same base and wattage ratings.
The BAY15d bayonet base found on the 1157NA and 1034NA features offset pins, a design that prevents incorrect single-filament bulbs from being seated in dual-filament sockets.
The natural amber glass designation on both the 1157NA and 1034NA means the amber color is produced by the glass envelope itself rather than by a painted or coated lens housing.
The P21W used in the 1992-1993 rear turn signal position is an ECE-standard single-filament bulb with a BA15s base, which has a single center pin and is not interchangeable with the BAY15d base used on dual-filament types.
The 1991 rear turn signal uses the P21/5W, an ECE-standard dual-filament bulb with a BAY15d base rated at 21W/5W, whereas the 1992-1993 rear position uses the P21W, a single-filament type with a different base, making these two rear bulbs physically incompatible with each other.
The ANSI-standard front bulbs (1157NA, 1034NA) and the ECE-standard rear bulbs (P21W, P21/5W) represent two separate standardization systems, and bulbs from one system are not rated as interchangeable with those from the other even when wattage values appear similar.