Plymouth Colt front turn signal bulbs use 1157 size while rear turn signal bulbs use 1156 size. The replacement chart covers 1983 to 1986 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Plymouth Colt uses the 1157 bulb for the front turn signal across the 1983-1986 model years.
The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output, meaning it carries two separate filaments operating at different wattages within a single housing.
Its BAY15d bayonet base features two offset pins at different heights, a design that prevents incorrect insertion and distinguishes it from single-filament bayonet types.
The rear turn signal on the Plymouth Colt for the same 1983-1986 model years uses the 1156 bulb.
The 1156 is a single-filament bulb rated at 12V and 21W, carrying only one filament dedicated to a single lighting function.
Its BA15s bayonet base uses two pins at equal heights, which is physically incompatible with the BAY15d socket used by the 1157, making the front and rear bulbs non-interchangeable despite their similar appearance.
Both the 1157 and 1156 are ANSI standardized bulbs recognized in the United States and Canada, meaning they conform to a defined set of electrical and physical specifications shared across manufacturers.
Although the 1157 and 1156 share the same 21W rating on their primary filaments, the 1157 carries an additional 5W filament, making it unsuitable as a direct replacement in a socket designed for the single-filament 1156.