The Ford Galaxie 500 front side marker bulb size includes 1157, 194, and 161 options, while rear side marker bulbs measure 194 or 161 in size. The replacement chart covers 1968 through 1974 vehicle production 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 194 bulb is the most frequently specified size across both front and rear side marker positions on the Ford Galaxie 500, appearing in multiple model years for each position. It is a T10 miniature wedge bulb rated at 12V and 3.78W, conforming to ANSI standards for the US and Canadian markets.
The 161 bulb is a T10 miniature wedge type sharing the same physical form factor as the 194 but rated at a significantly lower 1W output at 12V. Both the 1971 front and rear side marker positions on the Galaxie 500 specify the 161, making it the only year where both positions share this lower-wattage wedge type.
Although the 194 and 161 bulbs share the T10 wedge base, their wattage ratings differ substantially. The 194 draws 3.78W while the 161 draws only 1W, which means the two types are not electrically interchangeable despite their physical similarity.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W main filament and a 5W secondary filament. Its dual-filament design distinguishes it fundamentally from the single-filament wedge bulbs used in other positions on the Galaxie 500.
The 1157NA specified for the 1968 Ford Galaxie 500 front side marker is electrically and mechanically identical to the standard 1157, sharing the BAY15d bayonet base and the 12V, 21W/5W rating. The distinction is that the 1157NA features natural amber glass rather than a clear envelope, producing an amber output without relying on a colored lens.
Substituting a standard 1157 for a 1157NA, or vice versa, would affect the color output at the lens. The 1157NA achieves amber output through the glass itself, so using a clear 1157 in a position designed for the 1157NA would alter the emitted color if the housing lens is also clear.
The BAY15d bayonet base used by both the 1157 and 1157NA has offset pins, a design that prevents incorrect single-filament bulbs from being seated in the socket. This base type is not compatible with the wedge sockets used by the 194 and 161 bulbs.
The 1973 front side marker position specifies the 1157, a dual-filament bayonet bulb, while the 1972 front side marker position specifies the 194, a single-filament wedge bulb. These two consecutive model years therefore require entirely different socket types at the same position.
All four bulb types listed in the specifications, the 1157, 194, 161, and 1157NA, conform to ANSI standards applicable in both the United States and Canada, indicating consistent regulatory compliance across all specified positions and years.
The rear side marker position for the Ford Galaxie 500 specifies the 194 for 1969-1970 and 1972-1974, with the 161 specified solely for 1971. Because the 161 and 194 share the T10 wedge base, the socket itself is physically compatible across those years, though the wattage difference remains a consideration for correct replacement.