The Plymouth Gran Fury brake light utilizes 1157 and 2057 bulb sizes for the rear lighting system. Available information covers the production span from 1972 through 1989 for the specified vehicle components.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Plymouth Gran Fury uses the 1157 bulb as its brake light across the majority of its model years, spanning 1972-1980 and 1982-1989.
The 1157 is a dual-filament bulb operating at 12V with a 21W high filament and 5W low filament, mounted on a BAY15d bayonet base under the ANSI standard applicable in the US and Canada.
The dual-filament design of the 1157 allows a single bulb to serve both brake and tail light functions, with each filament handling a separate circuit.
The 1981 Gran Fury brake light specification calls for the 2057 bulb rather than the 1157 used in surrounding model years.
The 2057 shares the same BAY15d bayonet base as the 1157 but operates at higher wattages of 26.9W and 8W, making the two bulbs physically similar yet electrically distinct.
Although the 1157 and 2057 share the BAY15d base, substituting one for the other affects light output, and the two are not rated as interchangeable replacements.
The Center High Mount Stop Light on the 1987-1989 Gran Fury uses the 921, a single-filament wedge-type T15 bulb rated at 12V and 16W under the ANSI standard.
The 1986 Gran Fury (Center High Mount Stop Light) uses the P21W bulb, an ECE-standard single-filament bulb with a BA15s bayonet base rated at 12V and 21W.
The P21W and 921 are not interchangeable, as they differ in both base type and regional standard, with the P21W using a BA15s bayonet fitting and the 921 using a wedge base.
The shift from P21W in 1986 to the 921 in 1987 represents a change in both the base type and the governing bulb standard for the Gran Fury Center High Mount Stop Light.