Chevrolet Blazer Turn Signal Bulb Size

Additional Notes

• The 7444NA bulb is a dual-filament T20 wedge type rated at 12V with a 21W high filament and 5W low filament. Its natural amber glass produces the amber color required for turn signals without relying on a tinted lens, and it serves as the front turn signal for the Chevrolet Blazer in 2019, 2020, and 2022, as well as the rear turn signal in 2022.
• The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W. It shares the same T20 wedge form factor as the 7444NA but lacks a second filament and has no amber coating, making it a distinct fitment used exclusively at the rear turn signal position in 2019 and 2020.
• The 3157 and 3057 are both dual-filament T25 wedge bulbs rated at 12V with a 27W high filament and 7W low filament. Despite their near-identical electrical ratings, they are separate part numbers and are not interchangeable without verification, as the 3157 appears at the front and the 3057 at the rear across the 1995-2003 model years.
• The 3157NA and 3057NA variants carry the same T25 wedge construction and 27W/7W ratings as their non-NA counterparts but incorporate natural amber glass. The 3157NA was used at the front position in 1995-1997, and the 3057NA at the front in 1989-1991, with a conditional application in 1992 depending on headlamp type.
• The 2057 and 2057NA are dual-filament bulbs with a BAY15d bayonet base, rated at 12V, 26.9W high and 8W low. They are described as brighter variants of the 1157. The 2057NA adds natural amber glass. These bulbs are not wedge-type and require a socket compatible with the BAY15d base, which differs from the T25 wedge sockets used in adjacent model years.
• The 1992 Blazer presents a split fitment at both the front and rear turn signal positions depending on headlamp configuration. Vehicles equipped with sealed beam headlamps use the 2057, while those with halogen capsule headlamps use the 3057NA at the front and the 3057 at the rear, making headlamp type a necessary reference point before selecting a replacement bulb for that year.
• The 198 is a miniature T5 wedge bulb rated at 12V and 2W, substantially lower in wattage than all other bulbs in these specifications. It was used at both the front and rear turn signal positions on the Blazer from 1969 through 1974, with the exception of the rear position in 1969, 1970, and 1971, which used single-filament BA15s bayonet bulbs instead.
• The 1156 and 199 are both single-filament bulbs with a BA15s bayonet base rated at 12V and 21W, with the 199 described as a variant of the 1156. These appeared at the rear turn signal position in 1969, 1970, and 1971, a period during which the front position used the low-wattage 198 wedge bulb, meaning front and rear sockets on those vehicles are not compatible with the same bulb type.