Honda Motorcycle GL1200I Gold Wing Interstate Turn Signal Bulb Size
Honda Motorcycle GL1200I Gold Wing Interstate front turn signal bulb size 1034 and rear turn signal bulb size P21W, 1073. The replacement chart covers 1984 to 1987 production years with bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Honda Motorcycle GL1200I Gold Wing Interstate uses two distinct bulb standards across its turn signal positions: the ANSI standard, common in the US and Canada, and the ECE standard, used in Europe and worldwide.
The 1034 bulb is the sole front turn signal bulb across all four model years (1984-1987) of the GL1200I Gold Wing Interstate.
The 1034 is a dual-filament bulb operating at 12V with a 21/5W output, mounted on a BAY15d bayonet base. Its dual-filament design means it is capable of serving two lighting functions from a single housing.
The 1034 is classified as a variant of the 1157, a widely used automotive bulb. Despite this relationship, the two are not necessarily interchangeable, as variants within the ANSI system can differ in filament position, voltage draw, or base fit.
The rear turn signal position of the GL1200I Gold Wing Interstate uses different bulbs depending on the model year, with the 1984 model specifying the 1073 and the 1985-1987 models specifying the P21W.
The 1073 and P21W are both single-filament 12V bulbs sharing the BA15s bayonet base, yet they originate from different standards bodies and carry different wattage ratings: 13W for the 1073 and 21W for the P21W.
Because the 1073 and P21W share the BA15s base, physical installation may be possible across both types, but the wattage difference of 8W means the two bulbs are not electrically equivalent and substitution could affect turn signal flash rate or circuit load.
The front 1034 bulb uses a BAY15d base, which is physically distinct from the BA15s base used by both rear turn signal bulbs. The BAY15d base features offset pins to prevent incorrect installation of a single-filament bulb in a dual-filament socket.
The rear turn signal shift from the 1073 to the P21W between the 1984 and 1985 model years represents a change from an ANSI-rated 13W bulb to an ECE-rated 21W bulb, a notable difference in light output for the same circuit position.