The Ford E-250 side marker utilizes 168, 194, and 3357 bulb sizes for various lighting applications on the exterior of the vehicle. Available data covers a range from 2003 through 2014 for the specific components listed in the provided chart.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford E-250 front side marker uses two different bulb sizes depending on headlamp configuration for model years 2008-2014, with the 168 bulb specified for vehicles equipped with halogen capsule headlamps and the 194 bulb specified for vehicles equipped with sealed beam headlamps.
Both the 168 and 194 bulbs are ANSI-standard miniature wedge bulbs sharing the same T10 form factor and 12-volt operating voltage, though they differ in wattage: the 168 draws 4.9 watts while the 194 draws 3.78 watts.
Because the 168 and 194 share the T10 wedge base, physical fitment between the two is possible, but the wattage difference means they are not electrically identical and the headlamp configuration on the vehicle determines which rating is correct.
For model years 2004-2007, the Ford E-250 front side marker uses only the 168 bulb, with no headlamp-based split specification applied to those years.
From 1975-2003, the Ford E-250 front side marker uses only the 194 bulb across the entire model range, representing the longest continuous single-bulb fitment period in the front side marker specifications.
The rear side marker on the Ford E-250 uses the 3357 bulb for model years 1992-2014, a single-filament T25 wedge bulb rated at 12 volts and 27 watts, which operates at a substantially higher wattage than either front side marker bulb.
The 3357 is a T25 wedge bulb, a physically larger format than the T10 wedge used in the front side marker positions, making the front and rear side marker bulbs non-interchangeable by form factor alone.
For model years 1975-1991, the Ford E-250 rear side marker uses the 194 bulb, the same T10 miniature wedge type specified for the front side marker across much of the vehicle's history.
The rear side marker specification shifted from the 194 to the 3357 between the 1991 and 1992 model years, representing a significant change in bulb type, form factor, and wattage for that position.
The 194 bulb is the most broadly applied bulb across the full side marker specifications, appearing in the front side marker from 1975-2003 and in the rear side marker from 1975-1991, as well as in the front side marker of sealed beam headlamp variants from 2008-2014.