Autocar DS License Plate Bulb Size

The Autocar DS license plate light requires 1157 or 198 bulb sizes depending on the specific version of the heavy truck. Data for the lighting components covers the period from 1983 through 1988.

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
1985-1988	1157
1983-1984	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 DS uses two distinct bulb types for the license plate position across its production years: the 1157 and the 198.
The 1157 is an ANSI-standard dual-filament bulb rated at 12V with a 21W/5W output, mounted on a BAY15d bayonet base. The dual-filament design means it supports two separate brightness levels within a single housing.
The BAY15d bayonet base on the 1157 features offset pins, which prevents incorrect insertion and ensures polarity alignment during fitment.
The 198 is an ANSI-standard miniature wedge bulb in the T5 form factor, rated at 12V and 2W. Its wedge base is held in place by tension from the socket rather than a locking mechanism.
The 1157 and the 198 are not interchangeable. Their base types, wattage ratings, and physical forms are entirely different, and substituting one for the other is not compatible with the intended socket.
The Autocar DS (1985-1988) uses the 1157 bulb for the license plate position.
The 1983-1984 model years use the 198 bulb instead, reflecting a different socket configuration in the license plate housing for those years.
Both the 1157 and 198 conform to ANSI standards recognized in the United States and Canada, meaning replacements sourced within those markets are expected to meet the same specifications.
The 1157 operates at a significantly higher wattage than the 198, with its primary filament drawing 21W compared to the 198's 2W total draw. This difference reflects their distinct functional roles in the broader context of automotive lighting.