Plymouth Suburban Back Up Light Bulb Size

The Plymouth Suburban back up light utilizes 1129, 1073, and P21W bulb sizes for the rear illumination system. Data for the specific components covers the range from 1951 to 1961.

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
1960-1961	P21W
1959	1073
1958	P21W
1956-1957	1073
1951-1955	1129

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
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 Plymouth Suburban backup light specifications span model years 1951 through 1961, covering three distinct bulb types across that range.
The 1129 bulb is the most frequently specified type in these records, appearing in the Plymouth Suburban from 1951-1955. It follows the ANSI standard used in the US and Canada.
The 1129 is a dual-filament bulb rated at 12V with a 21/5W output, meaning it operates two separate filaments at different wattages. It uses a BAY15d bayonet base, which features two offset pins to prevent incorrect installation.
The 1129 is a variant of the 1157 bulb. These two types share the same BAY15d base but are not necessarily interchangeable, as wattage and filament ratings may differ between variants.
The 1073 bulb is specified for the Plymouth Suburban in 1956-1957 and again in 1959. It also follows the ANSI standard and uses a BA15s single-pin bayonet base rated at 12V, 13W.
The 1073 is a lower-wattage variant of the 1156 bulb. Despite sharing the same BA15s base type, the wattage difference means the two are not direct substitutes in applications where output levels are a factor.
The P21W bulb is specified for 1958, 1960, and 1961. It follows the ECE standard, which is used in Europe and internationally, rather than the ANSI standard applied to the 1073 and 1129 types.
The P21W is a single-filament bulb rated at 12V, 21W, and also uses a BA15s bayonet base. Although the P21W and 1073 share the same base type, their wattage ratings differ significantly, at 21W versus 13W respectively.
The shift between ANSI-standard and ECE-standard bulbs across different model years of the Plymouth Suburban indicates that the two standards are represented within the same vehicle nameplate, which is relevant when sourcing replacement parts.
The 1129 uses a BAY15d base, while both the 1073 and P21W use a BA15s base. These two base types are physically distinct and are not interchangeable, making base type a critical factor when selecting a replacement bulb for any given model year.