The Dodge Diplomat front and rear side marker bulb sizes are 168 and 168 or 1157 respectively, with the front utilizing a single bulb size designation. The replacement chart covers vehicle production spanning 1977 to 1989, detailing bulb specifications across the model's manufacturing period.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Dodge Diplomat uses the 168 bulb for the front side marker across its entire production span of 1977-1989.
The 168 is a T10 miniature wedge bulb rated at 12V and 4.9W, conforming to the ANSI standard recognized in both the United States and Canada.
The T10 wedge base requires no locking mechanism, as the bulb is held in place by the socket walls alone.
The rear side marker on the Dodge Diplomat uses the 168 bulb for most of its production years, with the exception of 1983 and 1984, which use the 1157 instead.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a high filament of 21W and a low filament of 5W.
The BAY15d bayonet base features two offset pins, which prevent incorrect insertion and distinguish it from single-filament bayonet types.
The 168 and 1157 are not interchangeable. They differ in base type, wattage, filament count, and socket design, making substitution between them incompatible without socket modification.
The wattage difference between the two bulb types is substantial. The 1157 high filament draws 21W compared to the 4.9W of the 168, reflecting a fundamentally different electrical load on the vehicle circuit.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized physical and electrical specifications across those markets.
The rear side marker socket on 1983-1984 models is designed for the BAY15d bayonet base of the 1157, while all other Diplomat model years use a wedge-type socket suited to the 168.