Toyota Mark II Back Up Light Bulb Size

The Toyota Mark II back up light uses bulb size 1156 for the rear lighting system. Data for the specific bulb application covers the range from 1973 to 1976.

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	US Type	EU Type	Shop
1973-1976	1156	P21W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W	Check Price

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Additional Notes

The 1156 is a single-filament bulb operating at 12 volts and 21 watts, fitted with a BA15s bayonet base. The BA15s designation indicates a single-contact bayonet cap with a 15mm base width, which positions and locks the bulb through a twist-and-lock mechanism.
The 1156 bulb follows the ANSI standard, meaning its physical and electrical specifications are governed by a standardized North American classification system recognized in both the United States and Canada.
The Toyota Mark II (1973-1976) uses the 1156 bulb across all four model years covered in the specifications for the back up light position.
Because the 1156 is a single-filament type, it serves only one lighting function per socket. This contrasts with dual-filament bulbs such as the 1157, which share a socket between two separate circuits. Substituting a dual-filament bulb in a single-filament application is not electrically compatible without modification.
The BA15s base is not interchangeable with the BA15d base. The BA15d variant carries two contact pins offset at different heights, while the BA15s carries only one. Inserting a BA15d bulb into a BA15s socket is physically prevented by this pin configuration difference.