The Ford F-600 front and rear turn signal bulb sizes include 1157, 1156, and 199 configurations for this commercial truck model. The replacement chart documents bulb size specifications across the 1970 to 1994 production range.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford F-600 front turn signal uses the 1157 bulb across the 1971-1994 model years, with the exception of 1979-1980, which use the 1156, and 1970, which uses the 199.
The 1157 is a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, fitted with a BAY15d bayonet base. Its two filaments serve separate functions within a single housing, which is why it is common in positions that combine turn signal and running light duties.
The 1156 is a single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base. Because it carries only one filament, it is dedicated to a single lighting function rather than a combined one.
The 199 is also a single-filament bulb rated at 12V and 21W with a BA15s bayonet base, and it is classified as a variant of the 1156 under the ANSI standard. It appears in the Ford F-600 front turn signal position for the 1970 model year and the rear turn signal for the 1972 model year.
The BAY15d base of the 1157 and the BA15s base of the 1156 and 199 are not interchangeable. The BAY15d base has two offset locating pins to ensure correct filament orientation, while the BA15s base has a single pin. A socket designed for one will not accept the other.
The rear turn signal of the Ford F-600 uses the 1156 across most of its model range, though the 1982, 1985-1987, and 1992 model years specify the dual-filament 1157 instead.
Because the rear turn signal position alternates between the 1156 and 1157 across different model years, the base type and filament count must be confirmed against the specific year before a replacement is selected, as the two bulbs are not socket-compatible.
All three bulb types listed in these specifications, the 1157, 1156, and 199, are governed by ANSI standards applicable in both the United States and Canada, indicating a standardized electrical and physical specification across those markets.