The Dodge D300 front turn signal uses bulb sizes 1157, 1034NA, or 198, while the rear turn signal uses 1157 or 198 sizes. The replacement chart covers 1975 through 1980 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 1157 bulb is a dual-filament type with a BAY15d bayonet base, rated at 12V with a 21W main filament and a 5W secondary filament. The dual-filament design allows a single bulb to serve both turn signal and running light functions.
The 1034NA shares the same BAY15d bayonet base and 12V/21W/5W electrical ratings as the 1157, but its glass envelope is tinted natural amber rather than clear. This amber tint produces a colored output without requiring an amber lens.
Because the 1034NA and 1157 share the same BAY15d base and identical voltage and wattage ratings, they are electrically and mechanically interchangeable in the Dodge D300.
The 198 is a miniature wedge bulb in the T5 form factor, rated at 12V and 2W. It is a single-filament type, meaning it serves only one lighting function per socket.
The 198 bulb uses a wedge base rather than a bayonet base, making it physically incompatible with sockets designed for the 1157 or 1034NA.
For the front turn signal on the Dodge D300, the specification changed from the 198 in 1975 to the 1034NA for 1976-1978, then to the 1157 for 1979-1980, reflecting two distinct socket and bulb transitions across the model's production span.
The rear turn signal used the 198 bulb from 1975-1978, then transitioned to the 1157 for 1979-1980, a single socket-type change over the covered years.
All three bulb types listed, the 1157, 1034NA, and 198, conform to ANSI standards applicable in both the United States and Canada.