Plymouth GTX Map Light Bulb Size

The Plymouth GTX map light requires bulb size 1895 or 90 depending on the specific version installed in the vehicle. Data for the bulb sizes covers the range from 1967 to 1971.

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
1971	1895
1967-1970	90

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 0.9W.	1895
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 13W.	90

Other Locations

Additional Notes

The Plymouth GTX map light uses two distinct bulb types across its production years: the 1895 and the 90, both conforming to ANSI standards recognized in the US and Canada.
The bulb 90 is a single-filament type with a BA15s bayonet base, rated at 12V and 13W. The BA15s designation indicates a single-contact bayonet cap with a 15mm base width.
The Plymouth GTX (1967-1970) uses the 90 bulb for the map light position.
The 1971 model year transitioned to the 1895 bulb, which is a T5 miniature wedge type rated at 12V and 0.9W.
The wattage difference between the two bulb types is substantial. The 90 bulb draws 13W, while the 1895 draws only 0.9W, reflecting a significant difference in light output and power consumption.
The 1895 uses a wedge base, while the 90 uses a BA15s bayonet base. These two base types are physically incompatible, and one bulb cannot be substituted for the other without a socket adapter or modification.
The T5 designation of the 1895 bulb refers to its tubular glass envelope size, measured in eighths of an inch, placing its width at approximately 5/8 of an inch.
The BA15s bayonet base of the 90 bulb is a single-contact design, distinguishing it from the BA15d double-contact variant. Using a double-contact bulb in a single-contact socket would result in incorrect fitment.