Ford Mainline front and rear turn signal bulbs utilized 1034 and 1154 size specifications. The replacement chart covers 1952 through 1956 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 Mainline uses two bulb types across its turn signal specifications: the 1034 and the 1154, both of which are dual-filament bulbs sharing the BAY15d bayonet base.
The BAY15d base is an offset twin-contact bayonet fitting, which physically distinguishes dual-filament bulbs from single-filament types and prevents incorrect installation of incompatible bulbs.
Both the 1034 and 1154 are ANSI-standardized bulbs recognized in the US and Canadian markets.
The 1154 is an older variant of the 1157 bulb type and is rated for either 6V or 12V operation, reflecting the transitional electrical systems found in vehicles of the early-to-mid 1950s.
The Ford Mainline (1952-1955) uses the 1154 bulb for both front and rear turn signals across all four of those model years.
The 1034 is a variant of the 1157 and operates at 12V with a 21/5W dual-filament output, indicating a higher-wattage filament for the turn signal function and a lower-wattage filament for a secondary function such as running or parking light.
The 1956 Ford Mainline uses the 1034 for both front and rear turn signals, replacing the 1154 used in prior model years.
Although the 1034 and 1154 share the same BAY15d base, their voltage ratings differ, and substituting one for the other without accounting for the vehicle's electrical system voltage could result in improper bulb performance.