Ford LTD front turn signal bulbs utilize 1034NA, 1157NA, or 1156 bulb sizes, while rear turn signal bulbs use 1157 or 1156 bulb sizes across multiple generations. The replacement chart covers vehicle production spanning 1965 to 1986 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 LTD front turn signal specifications span model years 1965 through 1986, with three distinct bulb types appearing across that range: 1034NA, 1157NA, and 1156.
The 1157NA is the most frequently specified front turn signal bulb for the Ford LTD, appearing in model years 1967, 1973-1977, 1979-1980, 1982, and 1985.
The 1157 and 1157NA share the same BAY15d bayonet base and 12V, 21W/5W dual-filament configuration, but the 1157NA carries natural amber glass, which produces the amber signal color directly from the bulb rather than relying on a colored lens.
The 1034NA is also a dual-filament bulb with a BAY15d bayonet base and natural amber glass, rated at 12V and 21/5W, making it a variant of the 1157 family. It appears in the front turn signal position for model years 1965, 1968, 1970-1972, 1978, 1984, and 1986.
Because the 1034NA, 1157NA, and 1157 all share the BAY15d bayonet base, their physical mounting interface is the same, though their glass color and filament output differ, which affects interchangeability in applications where lens color determines signal compliance.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W. Its base type differs from the BAY15d used by the 1157 family, meaning the two are not physically interchangeable despite similar voltage and wattage ratings.
The 1156 appears in the Ford LTD front and rear turn signal positions only for the 1983 model year, making it the least common bulb type across the full specification range.
The rear turn signal specification for the Ford LTD is uniform across all listed model years from 1965 through 1986, with the 1157 specified in every year except 1983, which uses the 1156.
A notable fitment consideration exists for the 1983 Ford LTD, as both the front and rear turn signal positions call for the 1156 rather than the dual-filament 1157 used in surrounding model years. Substituting a 1157 would introduce a second filament and a physically incompatible BAY15d base in place of the BA15s required by the 1156 socket.
The consistent use of the 1157 across the rear turn signal position for 21 of the 22 listed model years reflects its role as a standard dual-filament automotive signal bulb, where the lower 5W filament typically serves a parking or running light function alongside the 21W signal filament.