Chevrolet Citation Back Up Light Bulb Size

The Chevrolet Citation back up light requires bulb size 1156 or P21W depending on the specific version of the vehicle. Data for the bulb sizes covers the range from 1980 to 1983.

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
1980-1983	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 bulb is the sole back up light bulb type specified for the Chevrolet Citation across the 1980-1983 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 manufacturers.
The bulb operates on a 12-volt electrical system and draws 21 watts, which is consistent with standard automotive reverse lighting applications.
The 1156 uses a single filament, meaning it serves one lighting function only, as opposed to dual-filament bulbs that can serve two functions such as braking and running light simultaneously.
The base type is BA15s, a bayonet-style mount with a single contact pin. The "s" designation in BA15s denotes a single-contact base, distinguishing it from the BA15d, which carries two contact pins and is not interchangeable.
Because the BA15s base is a bayonet fitting, the bulb is installed by pressing inward and rotating to lock, rather than by threading.
The 1156 and the visually similar 1157 share the same BA15 bayonet shell size, but the 1157 uses a dual-filament, dual-contact base (BA15d) and is not a compatible substitute in a single-contact socket designed for the 1156.