The White/GMC WXLL uses 1157 bulb size for both front and rear turn signal applications. The replacement chart covers 1988 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 White/GMC WXLL uses the 1157 bulb for both its front and rear turn signals across the 1988-1995 model years.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope, allowing it to serve two distinct lighting functions at different wattages.
The 1157 operates on a 12-volt electrical system and draws 21 watts on its high-intensity filament and 5 watts on its low-intensity filament.
The 1157 uses a BAY15d bayonet base, which is an offset twin-pin mount. The two pins are positioned at different heights to ensure the bulb is inserted in the correct orientation, preventing filament misalignment.
The 1157 conforms to ANSI standards and is recognized in both the United States and Canada, reflecting a standardized specification shared across North American automotive applications.
Because the front and rear turn signal positions on the WXLL share the same 1157 specification, a single bulb type serves both locations on the vehicle.
The BAY15d base of the 1157 is not interchangeable with single-pin bayonet bases such as the BA15s, which is used by single-filament bulbs. Substituting a single-filament bulb in a dual-filament socket would result in loss of one lighting function.