The Ford P-350 front and rear turn signal bulbs utilize either 1141 or 1129 size specifications. The replacement chart covers 1952 through 1957 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford P-350 uses two distinct bulb types across its 1952-1957 model years for both front and rear turn signals: the 1141 and the 1129.
The 1141 is a single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base, and classified under the ANSI standard applicable in the US and Canada.
The 1129 is a dual-filament bulb rated at 12V with a 21/5W output, fitted with a BAY15d bayonet base, and is also an ANSI-standard bulb recognized in the US and Canada.
The BA15s base of the 1141 and the BAY15d base of the 1129 are not interchangeable. The BA15s has a single contact pin, while the BAY15d has two offset contact pins to support dual-filament operation.
The 1129 is noted as a variant of the 1157, though the two are not identical and should not be treated as direct substitutes without confirming base and wattage compatibility for a given application.
The Ford P-350 (1956-1957) uses the 1141 bulb for both front and rear turn signals, replacing the 1129 used in earlier model years.
The 1129 bulb was fitted to both the front and rear turn signal positions on the P-350 for model years 1952-1955.
The transition from the dual-filament 1129 to the single-filament 1141 between the 1955 and 1956 model years affects both front and rear turn signal positions simultaneously.