The White/GMC WHR uses a 1157 bulb size for both front and rear turn signal applications. This replacement chart covers vehicle production spanning 1989 to 1995.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The White/GMC WHR uses the 1157 bulb for both the front and rear turn signals across the 1989-1995 model years.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope, allowing it to serve more than one lighting function simultaneously or independently.
It operates on a 12-volt electrical system and carries a wattage rating of 21W on the high filament and 5W on the low filament, which corresponds to its turn signal and parking light roles respectively.
The 1157 uses a BAY15d bayonet base, a two-pin offset base design that prevents incorrect insertion by positioning the two pins at different heights along the base.
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 same bulb number applies to both the front and rear positions on the White/GMC WHR, a single bulb type serves all four turn signal sockets on the vehicle.
The BAY15d base is not interchangeable with single-pin bayonet bases such as the BA15s, and substituting a single-filament bulb in a dual-filament socket would result in incomplete circuit function.