Plymouth Belvedere Back Up Light Bulb Size

The Plymouth Belvedere back up light utilizes 1156, P21W, 1073, and 1129 bulb sizes depending on the specific production period. Available data for the lighting components spans from 1953 through 1971.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1967-1971	1156
1965-1966	1073
1958-1964	1156
1956-1957	1073
1953-1955	1129

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 13W.	1073
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.	1129

Other Locations

Additional Notes

The back up light bulb specifications for the Plymouth Belvedere span model years 1953 through 1971, covering three distinct ANSI-standard bulb types across that range.
The 1156 bulb is the most frequently specified type across the Plymouth Belvedere's back up light fitment history, appearing in fourteen of the nineteen model years documented.
The 1156 is a single-filament bulb rated at 12 volts and 21 watts, mounted on a BA15s bayonet base, which features a single locating pin on the base collar.
The 1073 bulb shares the same BA15s bayonet base as the 1156 but operates at a lower wattage of 13 watts, making the two physically interchangeable in terms of base fitment while differing in electrical output.
The Plymouth Belvedere used the 1073 bulb for the 1956-1957 and 1965-1966 model years, representing the lower-wattage back up light configuration within the lineup.
The 1129 bulb, specified for the 1953-1955 Plymouth Belvedere, is a dual-filament type rated at 12 volts with a 21/5-watt output, mounted on a BAY15d bayonet base.
The BAY15d base used by the 1129 bulb carries two offset locating pins, distinguishing it physically from the single-pin BA15s base of the 1156 and 1073 bulbs, which means the 1129 is not interchangeable with those two types.
The 1129 is classified as a variant of the 1157 bulb family, sharing its dual-filament construction and BAY15d base type.
All three bulb types specified across the Plymouth Belvedere's back up light history conform to ANSI standards applicable in both the United States and Canada.
The transition from the 1129 dual-filament bulb in 1953-1955 to the 1156 single-filament bulb beginning in 1958 reflects a change in socket base type, and parts from those two eras are not cross-compatible.