The Ford Explorer tail light utilizes unique bulb sizes 3757NA, 7440, 4057, 2458, and 3157 depending on the specific version of the vehicle. Provided data covers a range from 1991 to 2020.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 3157 bulb is the most historically prevalent type in the Ford Explorer's lower tail light position, covering model years 1991-2005 without interruption across that span.
Both the 3157 and 4057 are dual-filament T25 wedge bulbs rated at 12V with a 27W/7W output, meaning the higher wattage filament serves braking or running functions while the lower wattage filament serves the secondary function.
Because the 3157 and 4057 share the same T25 wedge base and identical wattage ratings, they are widely regarded within ANSI standards as functionally interchangeable in many applications, though the specifications list them as distinct fitments for different model years of the Ford Explorer.
The 2020 Ford Explorer lower tail light uses the 3757NA, a natural amber glass variant of the T25 dual-filament wedge family, which produces an amber color output through the glass itself rather than through a colored lens or coating.
The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W, making it a physically smaller and functionally different type from the T25 dual-filament bulbs used in surrounding model years of the lower tail light position.
The 2017-2018 Ford Explorer lower tail light uses the 7440, and because it is a single-filament bulb, it is not a drop-in replacement for dual-filament T25 types such as the 3157 or 4057, despite all being wedge-base designs.
The 194 is a miniature T10 wedge bulb rated at 12V and 3.78W, placing it in a substantially lower power class than any of the lower tail light bulbs listed in these specifications.
The 194 bulb appears exclusively in the upper tail light position for the Ford Explorer across the 2006-2010 model years covered in that sub-section, where its low wattage is consistent with indicator or courtesy lighting roles rather than primary brake or running light functions.
All five bulb types listed across these specifications conform to ANSI standards applicable in both the United States and Canada, indicating a shared regulatory framework governing their electrical and photometric performance.
The T10, T20, and T25 designations refer to the bulb envelope width in units of one-eighth of an inch, meaning a T25 bulb has a wider envelope than a T20, which in turn is wider than a T10, and these physical differences affect housing compatibility regardless of base type.