The Renault R18i front turn signal requires either 1157NA or 1034NA bulb size, while the rear turn signal uses 1157 bulb size. The replacement chart covers 1981 through 1986 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 1157 bulb is the most frequently specified type across these turn signal positions, appearing in all six model years for the rear turn signal of the Renault R18i.
The 1157 is a dual-filament bulb rated at 12V with a 21W high filament and a 5W low filament, mounted on a BAY15d bayonet base, which allows it to serve both signaling and running light functions from a single unit.
The BAY15d bayonet base uses an offset pin arrangement to ensure correct filament orientation during installation, preventing the high and low filaments from being wired to the wrong circuit.
The front turn signal of the Renault R18i used the 1034NA for the 1981-1985 model years, then changed to the 1157NA for the 1986 model year.
Both the 1034NA and 1157NA carry the "NA" suffix, which denotes natural amber glass rather than a clear envelope, meaning the amber color is produced by the glass itself rather than by the lens or housing.
The 1034NA is classified as a variant of the 1157, sharing the same BAY15d base, 12V rating, and 21W/5W dual-filament configuration.
Despite the functional and electrical similarities between the 1034NA and 1157NA, they are distinct part numbers, and fitment should follow the year-specific designations rather than treating them as freely interchangeable.
The rear turn signal retained the standard 1157 across all six model years, while the front position used amber-glass variants throughout, reflecting a difference in optical requirements between the two positions.