The White/GMC WXR uses 1157 bulb size for both front and rear turn signal applications. The replacement chart covers 1993 to 1995 model 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 1157 bulb is the sole bulb type specified across all turn signal positions on the White/GMC WXR for the 1993-1995 model years.
The 1157 is a dual-filament bulb, meaning it serves two lighting functions within a single unit, typically combining a higher-wattage filament for signaling with a lower-wattage filament for running or parking light duty.
The 1157 operates on a 12-volt electrical system and carries a wattage rating of 21W on its primary filament and 5W on its secondary filament.
The 1157 uses a BAY15d bayonet base, which is an offset twin-pin mount. The offset pin placement is a deliberate design feature that prevents incorrect filament orientation during installation.
The 1157 conforms to ANSI standards and is recognized in both the United States and Canada, placing it within a widely distributed specification category for North American vehicles.
The front and rear turn signal positions on the WXR share the same 1157 bulb specification across all listed model years, indicating a uniform electrical design between the two ends of the vehicle.
Because the BAY15d base uses an asymmetric pin layout, substitution with a single-pin bayonet bulb or a symmetrical twin-pin variant would result in an incompatible fit.