Mercury Zephyr License Plate Bulb Size

The Mercury Zephyr license plate light requires a 168 bulb size for proper illumination of the rear identification area. Data for the specified component covers the range from 1978 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	Bulb Size
1978-1983	168

Bulb Specifications

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

Other Locations

Additional Notes

The Mercury Zephyr uses the 168 bulb for its license plate light across the 1978-1983 model years.
The 168 is a miniature wedge-type bulb, classified under the T10 form factor, which refers to a tubular bulb roughly 10 eighths of an inch wide at its widest point.
The wedge base design means the bulb is held in place by the socket gripping the glass envelope directly, with no separate metal base or pins involved.
The 168 bulb operates at 12 volts and draws 4.9 watts, placing it in the low-wattage range typical of automotive indicator and illumination lamps.
The 168 is an ANSI-standardized bulb recognized in both the United States and Canada, meaning units sourced from either market share the same electrical and physical specifications.
The T10 wedge format is widely used across many vehicle makes and models, which means the 168 bulb is broadly available as a replacement part.
Although the T10 wedge platform is shared by several bulb numbers, wattage and voltage ratings can differ between them, so substituting a different T10 bulb number in the Mercury Zephyr may not produce equivalent performance.