The Subaru 1400 front and rear turn signal bulbs both utilize a 1034 size bulb for proper operation. The replacement chart covers vehicle production spanning 1973 to 1974.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1034 bulb is the sole bulb type across all listed positions and years for the Subaru 1400, appearing in both the front and rear turn signal applications for 1973-1974.
The 1034 is a dual-filament bulb, meaning it carries two separate filaments within a single envelope, allowing it to serve two distinct lighting functions at different wattages.
The 1034 operates at 12 volts with a 21/5W output, where the 21-watt filament handles the brighter signaling function and the 5-watt filament handles a lower-intensity function such as running or parking light duty.
The 1034 uses a BAY15d bayonet base, which is an offset twin-pin base design. The offset pin placement is a physical keying feature that prevents incorrect insertion of the bulb into the socket.
The 1034 is classified as an ANSI standard bulb recognized in both the United States and Canada, placing it within a standardized North American bulb numbering system.
The 1034 is a variant of the 1157 bulb. While the two share a similar dual-filament, BAY15d configuration, they are not confirmed as interchangeable within these specifications, and substitution without verification of exact electrical and physical compatibility carries fitment risk.