Ford Mustang II License Plate Bulb Size

The Ford Mustang II license plate bulb uses 194 and 168 sizes for illumination of the rear registration area. A replacement chart covering 1974 to 1978 model years documents the bulb specifications across the vehicle's production span.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1978	194
1977	168
1974-1976	194

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168

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Additional Notes

The Ford Mustang II uses two distinct bulb sizes for the license plate position across its production run: the 194 and the 168.
The 194 bulb is specified for the 1974-1976 and 1978 model years, making it the more frequently used of the two types in this application.
The 1977 model year is the sole exception, specifying the 168 bulb instead.
Both the 194 and 168 are ANSI-standardized bulbs recognized in the United States and Canada, and both share the T10 miniature wedge form factor.
The T10 wedge base is a bladeless, pin-free design that seats by friction, relying on the tapered plastic base to make contact within the socket.
Both bulbs operate on a 12-volt circuit, consistent with standard automotive electrical systems of that era.
Although the 194 and 168 share the same T10 wedge base and voltage rating, they differ in wattage: the 194 draws 3.78W while the 168 draws 4.9W.
The wattage difference means the two bulbs are not directly interchangeable without consideration, as the 168 places a higher load on the circuit than the 194.