Autocar C / DC License Plate Bulb Size

The Autocar C / DC license plate light requires bulb size 1157 or 198 depending on the specific version of the heavy truck. Data for the lighting components covers the period from 1981 to 1986.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1985-1986	1157
1981-1984	198

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157
ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 2W.	198

Other Locations

Additional Notes

The Autocar C / DC uses two distinct bulb types across its 1981-1986 model years for the license plate position: the 1157 and the 198.
The 198 bulb is a miniature wedge type with a T5 form factor, operating at 12V and rated at 2W, conforming to the ANSI standard used in the United States and Canada.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, operating at 12V with a 21W/5W output, also conforming to the ANSI standard used in the United States and Canada.
The BAY15d base of the 1157 features offset pins, which physically prevent incorrect installation of single-filament bulbs into the same socket.
The 1157 carries a significantly higher wattage than the 198, with its primary filament drawing 21W compared to the 198's 2W, reflecting a fundamental difference in bulb construction and intended application.
The Autocar C / DC (1981-1984) uses the 198 bulb for the license plate position across those four model years.
The 1157 is specified for the Autocar C / DC in 1985-1986, representing a different fitment from the preceding years.
The T5 wedge base of the 198 and the BAY15d bayonet base of the 1157 are physically incompatible with each other, meaning the two bulb types are not interchangeable.