Plymouth PB300 Back Up Light Bulb Size

The Plymouth PB300 back up light uses bulb sizes 1156, P21W, and 199 across various applications. Data for the specified components covers the range from 1975 to 1980.

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
1976-1980	1156
1975	199

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. Variant of 1156. 12V, 21W.	199

Other Locations

Additional Notes

The 1156 bulb is the back up light bulb size for the Plymouth PB300 across the 1976-1980 model years.
The 1975 Plymouth PB300 uses the 199 bulb for its back up light.
Both the 1156 and 199 are ANSI-standard bulbs recognized in the US and Canada.
Each bulb type operates at 12 volts with a 21-watt output, placing them in the same power class.
Both bulbs use a BA15s bayonet base, a single-contact base type where the pin is centered and the bulb locks into the socket with a twist.
The single-filament design of both bulbs means each serves one lighting function only, with no secondary filament for a dual-purpose role such as combined stop and tail lighting.
The 199 is classified as a variant of the 1156, meaning the two share the same electrical ratings and base type while differing in certain physical characteristics.
Because the 199 and 1156 share a BA15s base and identical voltage and wattage ratings, the distinction between them is relevant to physical fitment rather than electrical compatibility.