The White WHS front side marker bulb size measures 1157 or 194, while the rear side marker bulb size measures 194 for this commercial vehicle model. The replacement chart covers 1981 through 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 WHS uses two bulb types across its side marker positions: the 194 and the 1157. The 194 is a miniature wedge bulb in the T10 form factor, rated at 12V and 3.78W. The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with filaments drawing 21W and 5W respectively. Both conform to ANSI standards applicable in the US and Canada.
The 194 is by far the more prevalent bulb type across the White WHS side marker specifications, appearing in both front and rear positions across the majority of model years covered.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope. The 194, by contrast, is a single-filament wedge bulb. These two types are not interchangeable, as they differ in base design, wattage, and filament configuration.
The BAY15d bayonet base of the 1157 features two offset pins at different heights, a design that prevents incorrect insertion and distinguishes it physically from the wedge-style base of the 194.
For the White WHS front side marker, the 1988 model year uses the 1157 bulb. This differs from the 1981-1987 model years, which specify the 194 bulb with an "Except Conventional" fitment condition.
The "Except Conventional" notation on the 194 entries for 1981-1987 indicates that the specification applies only to non-conventional body configurations. The 1988 front side marker carries no such condition, specifying the 1157 without restriction.
The rear side marker for the 1988 White WHS specifies the 194 bulb without any fitment condition, while the 1981-1987 rear side marker entries carry the same "Except Conventional" qualifier seen on the front positions for those years.
The front and rear side markers share the same bulb type for the 1981-1987 model years, both specifying the 194 under the "Except Conventional" condition. The 1988 model year is the only one in these specifications where the front and rear positions call for different bulb types.