Ford Mustang II front and rear side marker bulbs utilize a 194 bulb size for illumination purposes. The replacement chart covers 1974 to 1978 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford Mustang II uses the 194 bulb for both front and rear side markers across its full production run of 1974-1978.
The 194 is a miniature wedge-type bulb, classified under the T10 form factor, which refers to a tubular glass envelope roughly 10 eighths of an inch wide.
The wedge base design means the 194 bulb is held in place by tension from the socket itself rather than by a separate metal base with pins, which is a common trait of low-current automotive lighting applications.
The 194 operates at 12 volts with a power draw of 3.78 watts, placing it in the low-wattage category typical of marker and courtesy lighting rather than primary illumination.
The 194 bulb conforms to ANSI standards recognized in both the United States and Canada, indicating a standardized specification for its electrical and physical characteristics.
Because the Ford Mustang II (1974-1978) uses the same 194 bulb in all four side marker positions, front and rear sockets accept the same replacement unit without distinction.