Plymouth Horizon License Plate Bulb Size

The Plymouth Horizon license plate light requires a 168 bulb size for proper illumination of the rear registration area. Available information covers the span from 1978 through 1990 for the specified vehicle.

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
1978-1990	168

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168

Other Locations

Additional Notes

The Plymouth Horizon uses the 168 bulb for the license plate position across all listed model years, spanning 1978-1990.
The 168 bulb follows the ANSI standard recognized in both the United States and Canada.
It is a miniature wedge type, classified under the T10 designation, which refers to a tubular bulb with a wedge base rather than a traditional pin or bayonet fitting.
The wedge base design means the bulb is held in place by the socket walls themselves, with no separate metal base or locking pins involved.
The 168 operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles of this era.
Its rated wattage of 4.9W places it in the low-power range, typical for exterior illumination functions such as license plate lighting that require visibility rather than high output.
The T10 wedge format is shared across a wide range of automotive applications, which means the 168 bulb is a widely available replacement type rather than a vehicle-specific part.
Because the same bulb size applies uniformly across the entire 1978-1990 production span of the Plymouth Horizon, no year-specific fitment distinctions exist within this model for the license plate position.