Ford F-150 Turn Signal Bulb Size

Additional Notes

• The Ford F-150 front and rear turn signal specifications span model years 1975 through 2022, covering four distinct bulb families: the 1034NA, 1157/1157NA, 3157/3157NA, 4057, 4257NA, and the 7443NA/7444NA series.
• Every bulb listed across both the front and rear positions is a dual-filament type, meaning each bulb serves two brightness levels within a single housing, typically one filament for the turn signal function and one for a secondary running or parking light function.
• The 3157NA is the most frequently specified front turn signal bulb in the Ford F-150 lineup, covering model years 2004-2014 and 1998-2005 in the rear, with the standard 3157 (without the natural amber glass coating) used in earlier rear positions from 1988 through 2004.
• The "NA" suffix on bulbs such as the 3157NA, 7444NA, and 4257NA denotes natural amber glass, meaning the amber color is produced by the glass envelope itself rather than by a clear bulb installed behind an amber lens. This distinction is relevant when the vehicle housing uses a clear or white lens rather than a colored one.
• The Ford F-150 (2021-2022) uses the 4257NA in both the front and rear turn signal positions, making it the only model year range in the specifications where a single bulb type is shared across both locations simultaneously.
• Front turn signal fitment for model years 2015-2020 carries a headlamp-type condition, with 7443NA specified for 2015 and 2017, and 7444NA specified for 2016, 2018-2020. The 7443NA and 7444NA are both T20 wedge bulbs rated at 12V and 21W/5W, and the difference between them relates to minor base or filament offset variations within the same T20 form factor.
• The 1157 uses a BAY15d bayonet base, which is a physically different mounting style from the wedge base used by the 3157, 4257NA, 7443NA, and 7444NA families. These two base types are not interchangeable, and substituting one for the other requires a socket adapter or housing modification.
• The 1034NA, specified for the Ford F-150 front turn signal in 1975-1977, is described as a variant of the 1157 and shares the BAY15d bayonet base. Despite the shared base type, the 1034NA and 1157 have different filament wattage ratings and are not direct substitutes for one another.
• The 4057 rear turn signal bulb, used from 2005-2014, shares the T25 wedge form factor and 12V/27W/7W rating with the 3157 but lacks the natural amber glass coating. The 4057 and 3157 are physically similar but are listed as separate ANSI part numbers, and fitment compatibility between them depends on the lens color of the specific housing.
• Rear turn signal fitment for model years 2015-2020 is conditioned on the presence of Halogen Capsule Headlamps, with the 3157 specified under that condition. This indicates the F-150 in those years was available with headlamp configurations that affected rear turn signal bulb selection.