Plymouth Grand Voyager Back Up Light Bulb Size

Additional Notes

• The Plymouth Grand Voyager backup light specifications cover model years 1987 through 2000 and reference three distinct bulb sizes across that span: the 1156, the 921, and the 3057.
• The 1156 bulb is a single-filament type with a BA15s bayonet base, rated at 12V and 21W. The bayonet base uses a twist-and-lock mounting style, which differs from the wedge-style bases found in the other two bulbs listed for this vehicle.
• The Plymouth Grand Voyager used the 1156 bulb for model years 1987-1990, making it the earliest fitment in the specifications.
• The 921 is a single-filament wedge bulb in the T15 form factor, rated at 12V and 16W. The T15 designation refers to the bulb body width expressed in eighths of an inch, placing it in a smaller wedge category than the T25.
• The 921 bulb applies to model years 1991-1995 on this vehicle.
• The 3057 is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W main filament and a 7W secondary filament. Despite having two filaments, only one is used in a backup light application, as backup lights do not require variable intensity.
• The Plymouth Grand Voyager transitioned to the 3057 bulb for model years 1996-2000.
• All three bulb sizes conform to ANSI standards recognized in both the United States and Canada, meaning they follow standardized electrical and physical specifications within those markets.
• The 921 and 3057 are both wedge-base bulbs, but they occupy different form factors, T15 and T25 respectively, and are not interchangeable with each other despite sharing the same base style category.
• The 1156 uses a bayonet base, which is physically incompatible with the wedge sockets used by the 921 and 3057, making cross-substitution between the 1156 and either wedge bulb impossible without socket modification.