The Ford F4 front and rear turn signal bulbs both utilize a 1129 size bulb for proper operation. The replacement chart covers 1950 through 1952 model 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 Ford F4 uses the 1129 bulb across both its front and rear turn signal positions for the 1950-1952 model years.
The 1129 is an ANSI-standardized bulb type, meaning its specifications are governed by a formal industry standard applicable in the United States and Canada.
The 1129 is a dual-filament bulb, which means it contains two separate filaments within a single envelope, allowing it to serve more than one lighting function.
The 1129 uses a BAY15d bayonet base, a two-pin offset base design that physically prevents incorrect insertion by positioning the two pins at different heights.
The 1129 operates at 12 volts with a wattage rating of 21/5W, where the higher wattage corresponds to the brighter filament and the lower wattage to the dimmer filament.
The 1129 is described as a variant of the 1157 bulb type. While the two share the same BAY15d base and general construction, they are not identical and may differ in voltage or wattage ratings, which affects direct interchangeability.