The Mercury Mountaineer side marker utilizes a 194 bulb size for illumination purposes within the lighting assembly. Data provided covers the specific span from 2002 through 2010 for the vehicle mentioned.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercury Mountaineer uses two distinct bulb types across its model years for side marker lighting: the 194 and the 916NA.
The 194 is an ANSI-standard miniature wedge bulb in a T10 form factor, rated at 12V and 3.78W, and is recognized for use in both the United States and Canada.
The 916NA is an ANSI-standard wedge bulb in a T15 form factor, rated at 12V and 18W, and features natural amber glass. It is also recognized for use in both the United States and Canada.
The T15 form factor of the 916NA is physically larger than the T10 form factor of the 194, and the wattage difference between the two types is substantial, making them non-interchangeable.
The Mercury Mountaineer (1997-2001) uses the 916NA bulb for both front and rear side markers.
From 2002-2010, the Mountaineer uses the 194 bulb for both front and rear side markers, replacing the higher-wattage 916NA used in earlier model years.
The natural amber glass of the 916NA produces its required color through the bulb envelope itself, whereas the 194 emits clear light and relies on the lens housing for any color output.
The front and rear side marker positions share the same bulb specification for every model year listed, meaning no positional difference exists between front and rear fitment requirements.