The Fiat 128 front and rear side marker bulbs both require a 194 size bulb for proper illumination. The replacement chart covers 1971 to 1979 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 Fiat 128 uses the 194 bulb for both the front and rear side marker positions across the 1971-1979 model years.
The 194 is a miniature wedge-type bulb, classified under the T10 designation, which refers to its tubular glass envelope nominally 10 eighths of an inch wide.
The wedge base design means the 194 bulb is held in its socket by the tension of the base contacts alone, with no separate metal bayonet or screw fitting required.
The 194 bulb operates at 12 volts and draws 3.78 watts, placing it among the lower-wattage bulbs used in automotive marker lighting applications.
The 194 is an ANSI-standardized bulb recognized in both the United States and Canada, meaning units sourced from either market conform to the same electrical and physical specifications.
Because the same 194 bulb is specified for both the front and rear side marker positions on the Fiat 128, a single bulb type services all four side marker locations on the vehicle.
T10 wedge bulbs share a base form factor with several other bulb numbers, though wattage and voltage ratings can differ between them, making it relevant to confirm the 194 designation specifically rather than substituting by base type alone.