Plymouth Valiant Back Up Light Bulb Size

The Plymouth Valiant back up light uses 1156, P21W, and 1073 bulb sizes according to the provided specifications for the lighting components. Available information covers the range from 1960 through 1976 for the specific vehicle and bulb data listed.

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
1967-1976	1156
1965-1966	1073
1963-1964	1156
1961-1962	1073
1960	1156

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

Other Locations

Additional Notes

The Plymouth Valiant backup light specifications cover model years 1960 through 1976, with two distinct bulb types appearing across that span: the 1156 and the 1073.
The 1156 is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base, and it serves as the backup light bulb for the Plymouth Valiant across the majority of listed model years.
The 1073 is also an ANSI-standard single-filament bulb with a BA15s bayonet base, rated at 12V but drawing only 13W, making it a lower-wattage variant relative to the 1156.
Despite the wattage difference, both the 1156 and 1073 share the same BA15s bayonet base type, which means the two bulbs are physically interchangeable in terms of socket fitment.
Because the 1073 operates at 13W versus the 1156 at 21W, substituting one for the other would result in a difference in light output, even though the base connection is mechanically compatible.
The Plymouth Valiant uses the 1156 for backup lighting in 1960, then the 1073 in 1961-1962, followed by the 1156 again in 1963-1964, the 1073 in 1965-1966, and the 1156 from 1967 through 1976.
The 1965-1966 Plymouth Valiant and the 1961-1962 Plymouth Valiant share the same 1073 backup light bulb specification, indicating a common fitment across those non-consecutive year groups.