The Geo Prizm front turn signal uses a 1156, 2057, or 1156NA bulb size, while the rear turn signal requires a 2057 bulb size. The replacement chart covers 1989 through 1997 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 2057 bulb is the most consistently used type across the Geo Prizm's turn signal specifications, appearing in the rear turn signal position for all model years from 1989-1997 and in the front turn signal position for the 1991-1992 model years.
The 2057 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a wattage split of 26.9W and 8W across its two filaments, making it suitable for combined signaling and running light functions.
The 1156 bulb is a single-filament type with a BA15s bayonet base, rated at 12V and 21W, and it serves as the front turn signal bulb for the Geo Prizm across the 1993-1997 model years.
The 1156NA shares the same electrical ratings and BA15s bayonet base as the standard 1156 but features natural amber-tinted glass, which produces an amber output without relying on a colored lens. It is specified for the front turn signal on the 1989-1990 Prizm.
Because the 1156 and 1156NA share the same base type and wattage, they are physically interchangeable, though substituting a clear 1156 for a 1156NA may affect the amber color output if the housing lens is also clear.
The BAY15d base of the 2057 and the BA15s base of the 1156 and 1156NA are not interchangeable, as the offset pins of the BAY15d base are designed to prevent incorrect installation of a single-filament bulb in a dual-filament socket.
The front turn signal of the Geo Prizm uses three distinct bulb types across its production run, while the rear turn signal position uses only the 2057 throughout the entire 1989-1997 span.
All bulb types listed in these specifications conform to ANSI standards applicable in both the United States and Canada, indicating consistent regulatory compliance across the North American market.