Ford Explorer Sport Trac front turn signal bulbs use 3457NA, 3357NA, or 3157NA bulb sizes, while rear turn signal bulbs use 4157 or 3157 sizes. The replacement chart covers 2001 through 2010 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 Ford Explorer Sport Trac uses five distinct bulb types across its front and rear turn signal positions: 3457NA, 3357NA, 3157NA, 4157, and 3157. All five conform to ANSI standards applicable in both the United States and Canada.
Four of the five bulb types, specifically the 3457NA, 3157NA, 4157, and 3157, are dual-filament T25 wedge bulbs rated at 12V with a 27W/7W output. The higher wattage filament serves the turn signal function, while the lower wattage filament typically serves a secondary lighting role such as parking or running light duty.
The 3357NA, used in the front turn signal position for the 2007 model year, is the only single-filament bulb among the five types. It is a T25 wedge bulb rated at 12V and 27W, meaning it does not carry a secondary filament for a running or parking light function.
The "NA" suffix on the 3457NA, 3357NA, and 3157NA designations indicates natural amber glass. This coloring is built into the glass envelope itself rather than relying on an amber-tinted lens housing to produce the required turn signal color.
The 4157 and 3157 bulbs, used in rear turn signal positions, do not carry the "NA" suffix, indicating their glass envelopes are clear rather than amber-tinted.
The front turn signal on the Ford Explorer Sport Trac transitioned through three different bulb types across its production span. The 3157NA was specified for model years 2001-2005, the 3357NA for 2007, and the 3457NA for 2008-2010.
Although the 3457NA and 3157NA share identical electrical ratings of 12V and 27W/7W and the same T25 wedge base, they carry different ANSI designations and are not interchangeable without confirming fitment, as the numeric codes reflect specific dimensional and performance standards.
The rear turn signal specification shifted from the 3157 to the 4157 between the 2005 and 2007 model years. Both are dual-filament T25 wedge bulbs with identical 12V and 27W/7W ratings, yet they hold separate ANSI designations and are not considered direct substitutes without verification.
The T25 wedge base format is common across all five bulb types in these specifications. This base style uses a plastic wedge rather than a metal pin configuration, and the bulb is retained by friction within its socket rather than by a bayonet or screw mechanism.
No rear turn signal entry exists in the specifications for the 2006 model year of the Ford Explorer Sport Trac, and no front turn signal entry exists for that year either, reflecting a gap in the listed model year coverage for both positions.