The Ford E-300 front turn signal requires a 1157NA bulb size while the rear turn signal uses a 1157 bulb size, with both positions accommodating 198 specifications. The replacement chart covers vehicle production years spanning 1969 to 1974.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford E-300 uses three distinct bulb types across its front and rear turn signal positions: the 1157NA, the 1157, and the 198.
The 1157 and 1157NA are both dual-filament bulbs sharing the BAY15d bayonet base and identical 12V, 21W/5W electrical ratings, meaning the filaments serve two separate functions, typically a brighter one for signaling and a dimmer one for running light duty.
The sole distinction between the 1157 and 1157NA is the glass envelope: the 1157NA features natural amber-tinted glass, while the 1157 uses clear glass. This difference affects the color of emitted light without altering the electrical characteristics.
The 198 is a miniature wedge bulb in the T5 form factor, rated at 12V and 2W, which places it in a significantly lower power class than the 1157-series bulbs used elsewhere on the same vehicle.
All three bulb types conform to ANSI standards applicable in both the United States and Canada.
For the Ford E-300, the front turn signal position transitioned from the 198 bulb in 1969-1972 to the 1157NA in 1973-1974.
The rear turn signal position on the Ford E-300 followed the same transition pattern, moving from the 198 in 1969-1972 to the 1157 in 1973-1974.
Although the 1157 and 1157NA share the BAY15d base and are electrically identical, substituting one for the other in the front turn signal position would alter the output color, as the 1157NA produces amber light through its tinted glass while the 1157 does not.
The 198 wedge bulb is not interchangeable with the 1157 or 1157NA, as it uses a wedge base rather than a BAY15d bayonet base and operates at a fraction of the wattage of the dual-filament bulbs.