The Pontiac Trans Sport tail light utilizes bulb sizes 3057, 194, and 2057 depending on the specific version of the component. Data for the provided specifications covers the period from 1990 through 1998.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Pontiac Trans Sport lower tail light draws from three distinct bulb types across its production run: the 2057, the 3057, and the 194.
The 2057 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a high/low wattage split of 26.9W and 8W. It is considered a brighter variant of the 1157 and follows the ANSI standard used in the US and Canada.
The 3057 is also a dual-filament bulb, but it uses a T25 wedge base rather than a bayonet mount. It operates at 12V with a 27W/7W filament split, making it functionally similar in output to the 2057 despite the different base type.
Because the 2057 and 3057 share similar wattage ratings but differ in base design, one cannot be substituted for the other without a socket mismatch. The bayonet base of the 2057 is physically incompatible with the wedge socket of the 3057.
The 194 is a single-filament miniature wedge bulb in a T10 form factor, rated at 12V and 3.78W. Its significantly lower wattage reflects a role distinct from the dual-filament stop/tail functions served by the 2057 and 3057.
For the lower tail light, the Trans Sport used the 2057 from 1990 through 1995, with the exception of 1992, which required the 194 instead.
The lower tail light specification shifted to the 3057 for the 1997-1998 model years, while 1996 carried both the 2057 and the 194 as separate lower tail light entries.
The upper tail light on the Trans Sport, covering the 1995-1996 model years, used the 194 exclusively, a single-filament miniature wedge bulb rather than one of the dual-filament types found in the lower position.
The presence of the 194 in both the upper tail light and certain lower tail light positions indicates that these sockets serve a lower-intensity function, consistent with the 194's single-filament, low-wattage design.
Installers sourcing a replacement for the lower tail light must confirm the exact model year before selecting between the 2057, 3057, or 194, as all three appear across the Trans Sport's production span and are not interchangeable with one another.