The Nissan 521 Pickup front turn signal requires a 1157 bulb size, while the rear turn signal uses either a 1073 or P21W bulb size. The replacement chart covers 1968 to 1972 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Nissan 521 Pickup uses the 1157 bulb for the front turn signal across all model years from 1968-1972.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output, fitted with a BAY15d bayonet base, and classified under the ANSI standard used in the US and Canada.
The dual-filament design of the 1157 allows a single bulb to serve two lighting functions simultaneously, which is why it is a common choice for front turn signal positions that also function as parking lights.
The rear turn signal of the Nissan 521 Pickup uses either the 1073 or the P21W bulb, depending on the model year.
The 1073 is specified for the rear turn signal in the 1968-1972 Nissan 521 Pickup for model years 1969, 1971, and 1972, while the P21W is specified for 1968 and 1970.
Both the 1073 and the P21W share the BA15s single-contact bayonet base, meaning the two bulbs are physically interchangeable in terms of socket fitment.
Despite sharing the same base type, the 1073 and P21W differ in wattage. The 1073 operates at 13W, while the P21W operates at 21W, which affects light output and electrical load.
The 1073 is an ANSI-standard bulb distributed primarily in the US and Canada, whereas the P21W follows the ECE standard used in Europe and other international markets.
The 1073 is described as a lower wattage variant of the 1156, a common single-filament bulb also using the BA15s base, which means the two are related in design but not directly interchangeable in applications where wattage tolerance is a factor.
The front and rear turn signal positions on the Nissan 521 Pickup use different base types. The front uses the BAY15d base via the 1157, while the rear uses the BA15s base via either the 1073 or P21W, making the front and rear bulbs non-interchangeable.