Honda Accord Back Up Light Bulb Size

The Honda Accord back up light utilizes bulb sizes 921, 1156, and P21W depending on the specific version required for the vehicle. Available data covers the period from 1976 through 2021 for the components 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
2021	921 (With Halogen Lamp Headlights)
2018-2020	921
1990-1991	1156
1982-1985	1156
1976-1978	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The 921 bulb is a T15 wedge-type unit operating at 12 volts and 16 watts, standardized under ANSI specifications for the US and Canadian markets.
The 1156 bulb is a single-filament unit with a BA15s bayonet base, operating at 12 volts and 21 watts, also standardized under ANSI specifications for the US and Canadian markets.
The BA15s bayonet base of the 1156 uses a single locating pin, which distinguishes it from the dual-pin BA15d base found on double-filament bulbs. These two base types are not interchangeable.
The T15 wedge base of the 921 relies on contact through its glass envelope rather than a separate metal base, making it physically incompatible with the bayonet socket used by the 1156.
The 1156 draws 21 watts versus the 921's 16 watts, meaning the two bulb types place different electrical loads on the vehicle's circuit and are not substitutes for one another.
The Honda Accord (2018-2021) uses the 921 bulb for the back up light position.
The 2021 Honda Accord fitment for the 921 bulb is specifically noted for vehicles equipped with halogen lamp headlights, indicating a trim or package dependency for that model year.
The 1156 bulb is specified for the Honda Accord across model years 1976-1978, 1982-1985, 1990, and 1991.