The Volvo 1800 uses 89 bulb size for both front and rear side marker positions. The replacement chart covers 1969 to 1973 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 Volvo 1800 uses the 89 bulb for both front and rear side marker positions across the 1969-1973 model years.
The 89 bulb is an ANSI-standardized type, meaning its physical and electrical specifications are governed by a recognized North American standard applicable in both the United States and Canada.
It is a single-filament bulb, indicating it serves one lighting function rather than combining two, such as stop and tail.
The 89 bulb uses a BA15s bayonet base, which is a single-contact bayonet mount with a 15mm collar. The "s" designation distinguishes it from the dual-contact BA15d variant and confirms it is not interchangeable with double-contact bayonet bulbs.
The 89 is described as a lower wattage variant of the 1156 bulb. While both share the BA15s base, the 1156 operates at a higher wattage, making the two types electrically distinct despite their physical similarity.
The 89 bulb operates at 12 volts and 13 watts, which places it within the standard low-voltage automotive electrical system range common to vehicles of this era.
Because the 89 and 1156 share the same BA15s base, physical fitment of a 1156 in place of an 89 is possible, but the wattage difference means the 1156 would draw more current than the Volvo 1800 side marker circuit was specified to accommodate.
The uniform use of the 89 bulb across both front and rear side marker positions on the Volvo 1800 means a single bulb type covers all four side marker sockets on the vehicle.