Chevrolet Blazer Tail Light Bulb Size

Additional Notes

• The 3057 bulb is an ANSI-standardized dual-filament wedge type with a T25 form factor, rated at 12V with a 27W high filament and 7W low filament. This wattage split allows it to serve both brake and running light functions within a single housing.
• The 2057 bulb uses a BAY15d bayonet base rather than a wedge mount, rated at 12V with filaments at 26.9W and 8W. The BAY15d base features two pins offset at different heights to prevent incorrect installation orientation.
• The 198 bulb is a miniature T5 wedge type rated at 12V and 2W, a significantly lower output than the 3057 or 2057 types used in later model years of the Chevrolet Blazer.
• The Chevrolet Blazer used the 198 bulb for tail lights across the 1969-1974 model years, the 2057 from 1987-1991, and the 3057 from 1993-2003, reflecting three distinct bulb families across the vehicle's production span.
• The 1992 Chevrolet Blazer is the only model year in these specifications where tail light bulb fitment depends on headlamp configuration. Vehicles equipped with halogen capsule headlamps use the 3057, while those with sealed beam headlamps use the 2057.
• Although the 3057 and 2057 are both dual-filament ANSI bulbs with similar wattage ratings, they use incompatible bases. The 3057 has a wedge base and the 2057 has a BAY15d bayonet base, making them non-interchangeable without a socket adapter.
• The 2057 is noted as a brighter variant of the 1157 bulb. Both share the BAY15d bayonet base, but the 2057 draws slightly more power on its high filament, producing greater light output in the brake light function.
• All three bulb types in these specifications conform to ANSI standards applicable in both the United States and Canada, indicating consistent regulatory compliance across the full range of listed model years.