The White WCM uses 1157 and 2057 bulb sizes for both front and rear turn signal applications. The replacement chart covers 1981 to 1988 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The White WCM uses two bulb types across its front and rear turn signal positions: the 1157 and the 2057, both of which are ANSI-standardized for the US and Canadian markets.
Both the 1157 and 2057 are dual-filament bulbs, meaning each contains a high-intensity filament for the turn signal function and a lower-intensity filament for a secondary function such as parking or running light duty.
Both bulb types share the BAY15d bayonet base, a two-pin offset base design that physically locks the bulb into the socket and ensures correct filament orientation.
Both bulbs operate on a 12-volt electrical system, consistent with standard automotive electrical architecture.
The 1157 carries a wattage rating of 21W on its primary filament and 5W on its secondary filament, while the 2057 draws 26.9W and 8W respectively, making the 2057 the higher-wattage variant of the two.
The White WCM (1981-1987) uses the 2057 bulb in both the front and rear turn signal positions across those model years.
The 1988 White WCM uses the 1157 bulb in both the front and rear turn signal positions, representing a change from the 2057 used in prior years.
Because the 1157 and 2057 share the same BAY15d bayonet base, they are physically interchangeable in the socket, though their filament wattages differ, which affects light output.