The Austin Mini front turn signal requires a 1034 bulb size while the rear turn signal uses a 1073 bulb size. This replacement chart covers vehicle production spanning 1964 to 1966.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Austin Mini uses two distinct bulb types across its front and rear turn signal positions for the 1964-1966 model years: the 1034 at the front and the 1073 at the rear.
The 1034 is a dual-filament bulb operating at 12V with a 21/5W output, meaning it carries separate filaments for two brightness levels within a single housing.
The 1034 uses a BAY15d bayonet base, an offset two-pin fitting that prevents incorrect installation by ensuring only one rotational orientation is possible.
The 1034 is classified as a variant of the 1157 under the ANSI standard applicable to the US and Canada, indicating close but not identical electrical and physical characteristics relative to that more widely referenced type.
The 1073 is a single-filament bulb operating at 12V and 13W, producing one fixed output level with no secondary filament.
The 1073 uses a BA15s bayonet base, a single-pin fitting that differs structurally from the dual-pin BAY15d base of the 1034, making the two bulbs non-interchangeable despite both using bayonet-style mounts.
The 1073 is classified as a lower wattage variant of the 1156 under the same ANSI standard, drawing less power than the 1156 while sharing its single-filament, BA15s configuration.
Because the 1034 and 1073 share a 12V operating voltage but differ in base type, filament count, and wattage, substituting one for the other in the Austin Mini is not supported by these specifications.