The Volvo S90 brake light requires a unique 1156 bulb size for the lighting system. Data for the specific component covers the range from 1997 through 1998.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Volvo S90 uses the 1156 bulb for both the brake lights and the center high mount stop light across the 1997-1998 model years.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, which is consistent with its use in dedicated brake and stop light positions rather than combined tail/brake applications.
The 1156 operates at 12 volts and 21 watts, a standard output level for incandescent stop light applications in passenger vehicles of that era.
The 1156 uses a BA15s bayonet base, a single-contact mount that differs from the dual-contact BA15d base found on two-filament bulbs such as the 1157. These two base types are not interchangeable despite their similar physical appearance.
The 1156 conforms to ANSI standards applicable in the United States and Canada, indicating the bulb meets regulated performance and dimensional criteria for those markets.
The same 1156 bulb type is specified for both the standard brake light position and the center high mount stop light on the S90, meaning a single bulb type covers all three stop light positions on the vehicle.