Mercury Topaz front side marker bulbs use 2357NA, 1157, or 194 bulb sizes, while rear side marker bulbs use 2357 or 1157 sizes. The replacement chart covers 1984 through 1994 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 2357NA is the most frequently specified bulb across the Mercury Topaz side marker data, appearing as the front side marker fitment for model years 1986-1987 and 1992-1994.
The 2357NA is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a wattage draw of 26.9W on the high filament and 8W on the low filament, and features natural amber glass rather than a clear envelope.
The natural amber glass of the 2357NA produces a colored output without the use of an external lens filter, which distinguishes it from the otherwise electrically identical 2357.
The 2357 and 1157 share the same BAY15d bayonet base and dual-filament configuration, making them physically interchangeable in terms of socket fitment, though their wattage ratings differ.
The 1157 is rated at 12V with filaments drawing 21W and 5W, while the 2357 draws 26.9W and 8W, making the 2357 the higher-output variant of the two.
For the Mercury Topaz rear side marker, the 2357 is specified for 1986-1988, while the 1157 covers 1984-1985, reflecting a shift between two BAY15d dual-filament bulbs across those years.
The 194 is a single-filament miniature wedge bulb of the T10 type, rated at 12V and 3.78W, and is specified solely for the 1984 Mercury Topaz front side marker position.
The 194 wedge base is physically incompatible with the BAY15d bayonet socket used by the 2357NA, 2357, and 1157, meaning the 1984 front side marker socket is a different type than those used in all other listed years.
All four bulb types listed across these specifications conform to ANSI standards applicable in both the United States and Canada.
The front and rear side marker positions do not always share the same bulb specification within a given model year, as seen in 1985 where both positions use the 1157, while in 1986-1987 the front uses the 2357NA and the rear uses the 2357.