The Autocar ACL uses 1156 and 199 bulb sizes for front turn signal applications and 1157 and 198 bulb sizes for rear turn signal applications. A replacement chart covering 1981 through 1988 documents the turn signal bulb size specifications for this vehicle model across its production years.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Autocar ACL front turn signal uses the 1156 bulb for 1981 and 1983-1988, and the 199 bulb for 1982. Both are single-filament bulbs rated at 12V and 21W, sharing the same BA15s bayonet base.
The 199 bulb is an ANSI-standard variant of the 1156, meaning both share the same base type, voltage, and wattage rating, though they carry distinct part numbers.
The rear turn signal on the Autocar ACL uses the 1157 bulb for 1985-1988 and the 198 bulb for 1981-1984.
The 1157 is a dual-filament bulb rated at 12V with a 21W high filament and a 5W low filament, mounted on a BAY15d bayonet base. The offset pins of the BAY15d base prevent incorrect installation of the bulb.
The 198 is a miniature wedge bulb of the T5 type, rated at 12V and 2W, which is considerably lower in wattage than the 1157 it replaced in the rear turn signal position from 1985 onward.
The 1156 and 1157 bulbs use different bayonet bases, BA15s and BAY15d respectively, making them physically non-interchangeable despite sharing the same 21W high-filament wattage.
All four bulb types listed in these specifications conform to ANSI standards applicable in both the United States and Canada.
The front turn signal position uses only single-filament bulbs across all listed years, while the rear turn signal position uses both single-function and dual-filament types depending on the model year.