Ram 1500 Turn Signal Bulb Size

Additional Notes

• The 3157NA is the most frequently specified front turn signal bulb across the Ram 1500, covering model years 2013-2018, 2021, and 2023-2024. It is a dual-filament T25 wedge bulb rated at 12V with a 27W high filament and 7W low filament, and its natural amber glass produces the amber signal color without relying on a colored lens or painted coating.
• The "NA" suffix in bulb designations such as 3157NA and 7440NA indicates natural amber glass, distinguishing these bulbs from their clear-glass counterparts, the 3157 and 7440. The amber tint is built into the glass envelope itself, which affects color output and means the NA and non-NA variants are not interchangeable where a specific color output is required by the vehicle's optical design.
• The 3057 and 3157 share the same T25 wedge base and 12V/27W/7W dual-filament electrical ratings, but they differ in filament orientation and light distribution characteristics. For the Ram 1500 (2013-2018), the rear turn signal uses the 3057 while the front uses the 3157NA, so the two positions are not interchangeable despite their similar specifications.
• The 7440NA and 7444NA are both T20 single- and dual-filament wedge bulbs respectively, operating at 12V. The 7444NA adds a 5W low filament to the 7440NA's 21W primary filament, making it a dual-filament variant. The 2019 Ram 1500 front turn signal specifies the 7444NA with halogen capsule headlamps, while the 2020 model uses the single-filament 7440NA, indicating these two bulbs serve different circuit configurations and are not substitutes for one another.
• The 2012 and 2011 Ram 1500 front turn signal fitment depends on headlamp count. The two-headlamp configuration uses the 3157, while the four-headlamp configuration uses the 3157NA. Since the 3157 has a clear glass envelope and the 3157NA has a natural amber envelope, selecting the incorrect variant for a given headlamp configuration would affect the color output at the turn signal position.
• The 921 is the smallest bulb in these specifications, a T15 wedge type rated at 12V and 16W with a single filament. It appears only in the 2023 Ram 1500 rear turn signal position, and its T15 base is physically incompatible with the T20 and T25 sockets used in all other positions listed.
• All bulbs in these specifications conform to ANSI standards applicable in both the United States and Canada, meaning their base dimensions, filament positions, and electrical ratings follow a standardized format shared across compliant manufacturers.
• The front and rear turn signal positions on the Ram 1500 do not consistently use the same bulb type within a given model year. For example, the 2021 model year uses the 3157NA at the front and the 7440NA at the rear, and the 2019 model year uses the 7444NA at the front and the 3157 at the rear, confirming that front and rear positions require independent verification before replacement.