The Autocar DS uses the 97 bulb for both front and rear side marker positions across the 1983-1988 model years.
The 97 is an ANSI-standardized bulb recognized in both the United States and Canada, operating at 12 volts with a 13-watt output.
It uses a BA15s bayonet base, which is a single-contact base type. The "s" in BA15s denotes a single center contact, as opposed to the dual-contact BA15d variant.
The 97 is a single-filament bulb, meaning it serves one lighting function rather than switching between two brightness levels as a dual-filament bulb would.
The 97 is classified as a variant of the 1156 bulb. While both share the BA15s base, the 97 operates at a lower wattage than the standard 1156, which is rated at 26.9 watts.
Because the 97 and 1156 share the same BA15s base, physical fitment between the two is possible, but the difference in wattage means they are not electrically equivalent and are not interchangeable without consideration of circuit compatibility.
The uniform use of the 97 across all six model years and across both the front and rear side marker positions means a single bulb type covers all side marker replacements on the 1983-1988 Autocar DS.