Chevrolet Nomad Back Up Light Bulb Size

The Chevrolet Nomad back up light bulb size specifications include 1156 and 1073 bulb options for this vehicle model. The replacement chart covers 1955 through 1961 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.

Bulb Size by Year Range

Years	Bulb Size
1959-1961	1156
1955-1958	1073

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 Chevrolet Nomad uses two distinct bulb types across its model years for the back up light position: the 1073 and the 1156.
Both the 1073 and 1156 are ANSI-standardized bulbs recognized in the United States and Canada, each using a BA15s single-contact bayonet base.
The BA15s base features a single contact point at the base tip, which distinguishes it from dual-contact bayonet bases and makes polarity orientation straightforward during installation.
Both bulb types operate on a 12-volt electrical system and use a single filament, meaning each serves one lighting function rather than combining two.
The 1073 and 1156 share the same BA15s base type, but they are not interchangeable due to a significant wattage difference: the 1073 draws 13W while the 1156 draws 21W.
The Chevrolet Nomad (1955-1958) uses the 1073 bulb for the back up light, reflecting the lower 13W output associated with that generation.
The 1959-1961 Nomad transitions to the higher-output 1156 bulb at 21W, representing a change in the back up light specification relative to earlier model years.
Because the 1073 and 1156 share a physically compatible BA15s base, the 1156 can fit into a 1073 socket mechanically, but the increased wattage may exceed the design tolerance of the original wiring and socket in 1955-1958 vehicles.