Austin Princess Turn Signal Bulb Size

The Austin Princess 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.

Front Turn Signal

Years	Bulb Size
1964-1966	1034

Rear Turn Signal

Years	Bulb Size
1964-1966	1073

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.	1034
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 13W.	1073

Other Locations

Additional Notes

The Austin Princess uses two distinct bulb types across its turn signal system for the 1964-1966 model years: the 1034 at the front and the 1073 at the rear.
The 1034 is an ANSI-standard bulb recognized in the US and Canada. It operates on a 12V circuit and carries a dual-filament design rated at 21/5W, meaning one filament handles a higher load while the other handles a lower one.
The 1034 uses a BAY15d bayonet base. The offset pins of the BAY15d base are a physical safeguard against incorrect installation, as the asymmetric pin placement allows the socket to accept the bulb in only one orientation.
The 1034 is described as a variant of the 1157, a widely available bulb type. The two share the same dual-filament, BAY15d configuration, though they are not confirmed as direct substitutes within these specifications.
The 1073 is also an ANSI-standard bulb recognized in the US and Canada. It is a single-filament type rated at 12V and 13W, dedicated solely to the rear turn signal function on the Austin Princess across the 1964-1966 model years.
The 1073 uses a BA15s bayonet base, which features two pins positioned symmetrically. Unlike the BAY15d base on the 1034, the BA15s base is not offset, reflecting the single-filament nature of the bulb.
The 1073 is described as a lower wattage variant of the 1156. The 1156 is a common single-filament, BA15s bulb, and the 1073 draws less power at 13W compared to the 1156's typical 26.9W rating.
The front and rear turn signal bulbs on the Austin Princess are not interchangeable. The 1034 has a dual-filament construction and a BAY15d base, while the 1073 has a single-filament construction and a BA15s base, making the two physically and electrically incompatible with each other's sockets.