Dodge St. Regis Back Up Light Bulb Size

The Dodge St. Regis back up light uses a 1156 bulb size for this specific lighting component. The replacement chart covers vehicle production spanning 1979 to 1981.

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
1979-1981	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The 1156 is the sole bulb type listed for the Dodge St. Regis backup light across the 1979-1981 model years.
The 1156 is an ANSI-standardized bulb recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical parameters shared across those markets.
It is a single-filament bulb, which is typical for backup lights, as the function requires only one consistent light output state rather than the dual-intensity operation found in combination stop/tail bulbs.
The 1156 uses a BA15s bayonet base, a single-contact fitting where the bulb is inserted and rotated to lock into place. The "s" in BA15s denotes a single contact pin, distinguishing it from the dual-contact BA15d variant.
The bulb operates at 12 volts and draws 21 watts, consistent with standard automotive electrical systems of that era.
Because the BA15s base has only one contact pin, substituting a BA15d bulb is not a direct fit, as the pin configuration differs between the two base types.