The White/GMC WXLL uses a 1157 bulb size for front side marker applications and a 194 bulb size for rear side marker applications. The replacement chart covers 1988 to 1995 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/GMC WXLL uses the 1157 bulb for the front side marker position across the full 1988-1995 model range.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with filaments drawing 21W and 5W respectively.
The BAY15d bayonet base features offset pins, a physical design that prevents incorrect single-filament bulbs from seating in the socket.
The rear side marker position on the WXLL uses the 194 bulb across the same 1988-1995 model range.
The 194 is a miniature wedge-type bulb in the T10 form factor, rated at 12V and 3.78W, intended for low-intensity marker and clearance applications.
Both the 1157 and 194 are ANSI-standardized bulbs recognized in the United States and Canada, meaning replacement units from multiple manufacturers conform to the same electrical and physical specifications.
The front and rear side marker positions on the WXLL require different bulb types, and the two are not interchangeable due to differences in base design, wattage, and filament configuration.
The single-filament 194 wedge bulb used at the rear draws significantly less power than either filament of the 1157, reflecting the lower luminous output required for a rear side marker compared to a front position that may also serve a turn signal function.