The Autocar DS front turn signal uses a 1156 or 199 bulb size, while the rear turn signal requires a 1157 or 198 bulb size. The replacement chart covers 1983 to 1988 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 1156 bulb is the most frequently specified front turn signal bulb across the Autocar DS model years covered, appearing in five of the six listed years for that position.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W under the ANSI standard applicable in the US and Canada.
The 199 bulb, specified for the 1984 Autocar DS front turn signal, shares the same BA15s bayonet base, voltage, and wattage as the 1156, as it is classified as a variant of that bulb type.
Despite the electrical and mechanical similarities between the 1156 and 199, they are listed as distinct ANSI bulb types, and substitution between them should be confirmed against the vehicle's socket and circuit requirements before use.
The rear turn signal on the Autocar DS uses a dual-filament bulb for model years 1985-1988, specified as the 1157, which operates on a BAY15d bayonet base at 12V with filaments rated at 21W and 5W respectively.
The BAY15d base of the 1157 is not interchangeable with the BA15s base of the 1156 or 199, as the offset pin arrangement of the BAY15d is physically distinct and prevents cross-installation.
The 198 bulb, specified for the rear turn signal in 1983-1984, is a miniature wedge type in the T5 form factor, rated at 12V and 2W, which places it in a substantially different power class than the other bulbs listed in these specifications.
The low wattage of the 198 bulb at 2W contrasts sharply with the 21W output of the 1156, 199, and 1157 types, indicating a fundamentally different lamp construction and socket type that is not interchangeable with any of the bayonet-base bulbs in these specifications.
All four bulb types listed across these specifications conform to ANSI standards recognized in the US and Canada, meaning they follow standardized base configurations, voltage ratings, and filament wattages within that regulatory framework.
The rear turn signal position on the Autocar DS transitions from the 198 wedge bulb in 1983-1984 to the 1157 dual-filament bayonet bulb in 1985-1988, representing a change in both bulb format and wattage for that position.