The Freightliner FL60 front turn signal uses a 1156 bulb size while the rear turn signal requires a 1157 bulb size. The replacement chart covers vehicle production years spanning 1991 to 2004 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 Freightliner FL60 uses the 1156 bulb for the front turn signal across all listed model years from 1991-2004, and the 1157 bulb for the rear turn signal across the same span of years.
The 1156 is a single-filament bulb operating at 12V and 21W, fitted with a BA15s bayonet base, and recognized under ANSI standards in both the United States and Canada.
The 1157 is a dual-filament bulb rated at 12V with filaments drawing 21W and 5W respectively, fitted with a BAY15d bayonet base, and also recognized under ANSI standards in the United States and Canada.
The BA15s base of the 1156 and the BAY15d base of the 1157 are not interchangeable. The BAY15d base features offset locating pins that prevent incorrect installation, while the BA15s base has symmetrical pins suited only to single-filament sockets.
The dual-filament design of the 1157 allows the rear turn signal housing to serve two brightness levels, with the higher 21W filament typically active during signaling and the lower 5W filament used for a secondary function such as running or parking light operation.
Because the 1156 and 1157 share the same 12V operating voltage and the same 21W primary wattage, substituting one for the other in a given socket is an electrical risk, as the socket wiring and base configuration are specific to each bulb type.