The Geo Prizm front side marker bulb uses a 194 size, while rear side marker applications accommodate either 168 or 194 bulb sizes. The replacement chart covers vehicle production spanning 1989 to 1997 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 Geo Prizm uses two bulb types across its side marker positions: the 194 and the 168, both of which are ANSI-standardized miniature wedge bulbs of the T10 form factor rated at 12 volts.
Although the 194 and 168 share the same T10 wedge form factor, they are not electrically identical. The 194 draws 3.78 watts while the 168 draws 4.9 watts, making them non-interchangeable despite their physical similarity.
The 194 bulb is the front side marker size for the Geo Prizm across all model years covered in the specifications, spanning 1989-1997.
The rear side marker position on the Geo Prizm uses the 194 bulb for the 1989-1992 model years and transitions to the 168 bulb for the 1993-1997 model years.
The 194 and 168 designations are ANSI standard codes recognized in both the United States and Canada, meaning the bulb specifications conform to a defined industry standard rather than a proprietary sizing system.
The T10 wedge base type used by both bulbs does not rely on metal pins or a screw shell for retention. Instead, the bulb body itself acts as the connector, fitting directly into a wedge-style socket.