The Autocar C / DC front turn signal bulb size measures 1156 or 199, while the rear turn signal bulb size measures 1157 or 198. The replacement chart covers vehicle production years spanning 1981 to 1986.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The front turn signal on the Autocar C / DC uses two distinct bulb types across its model years, with the 1156 fitted in 1981 and 1984-1986, and the 199 fitted in 1982-1983.
The 1156 is a single-filament bulb rated at 12V and 21W, mounted on a BA15s bayonet base, and is classified under the ANSI standard applicable to the US and Canada.
The 199 shares the same BA15s bayonet base, voltage, and wattage as the 1156, as it is an ANSI-classified variant of that bulb type, making the two functionally similar in electrical terms.
Despite the electrical similarity between the 1156 and 199, they are listed as separate fitments for specific model years, so substitution between them warrants verification against the vehicle's socket and housing requirements.
The rear turn signal on the Autocar C / DC uses the 1157 in 1985-1986 and the 198 in 1981-1984, representing a significant difference in bulb technology between those two groups.
The 1157 is a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base, which is a different base type from the BA15s used by the 1156 and 199.
The BAY15d base of the 1157 is offset-pin, meaning it is not interchangeable with the single-pin BA15s base used by the front turn signal bulbs, even though both are bayonet-style mounts.
The 198 is a miniature wedge bulb of the T5 form factor, rated at 12V and only 2W, placing it in a substantially lower power class than all other bulb types listed in these specifications.
The wedge-mount design of the 198 is mechanically incompatible with the bayonet bases used by the 1156, 199, and 1157, as wedge bulbs seat directly into a friction-fit socket without any base pins or locking mechanism.
All four bulb types in these specifications conform to ANSI standards for the US and Canadian markets, indicating they are standardized for North American automotive applications.