The Ford Explorer Sport Trac brake light utilizes bulb sizes 4157, 2458, and 3157 depending on the specific version of the vehicle. Data for the components covers the range from 2001 to 2010.
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 two distinct bulb types across its model years for the brake light position: the 4157 for 2007-2010 and the 3157 for 2001-2005.
Both the 4157 and 3157 are ANSI-standard dual-filament wedge bulbs classified under the T25 form factor, each rated at 12V with a 27W/7W output split between the high and low filaments.
The dual-filament design of the 4157 and 3157 allows a single bulb to serve both the brake light function and a secondary lower-intensity function, such as a tail or parking light, within the same housing.
Although the 4157 and 3157 share identical voltage and wattage ratings, they are not confirmed as interchangeable for the Explorer Sport Trac, as each is specified for a distinct set of model years.
The center high mount stop light on the Ford Explorer Sport Trac uses the 921 bulb for 2007-2010 and the 922 bulb for 2001-2005.
Both the 921 and 922 are ANSI-standard single-filament wedge bulbs in the T15 form factor, each rated at 12V and 16W.
The T15 wedge form factor of the 921 and 922 is physically smaller than the T25 form factor used by the 3157 and 4157, reflecting the different housing requirements of the center high mount stop light versus the main brake light position.
The 921 and 922 share the same voltage and wattage ratings, though the specifications assign each to separate model year ranges without indicating cross-compatibility between them.