Isuzu I-Mark License Plate Bulb Size

The Isuzu I-Mark license plate light utilizes 168, 194, and 89 bulb sizes depending on the specific version of the vehicle. Available data for the lighting components covers the range from 1981 through 1989.

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
1987-1989	168
1986	194
1985	89
1984	194
1983	89
1981-1982	194

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 13W.	89

Other Locations

Additional Notes

The Isuzu I-Mark uses three distinct bulb types across its license plate lighting specifications: the 168, 194, and 89.
The 168 and 194 are both T10 miniature wedge bulbs operating at 12V, making them physically similar in form factor despite differing in wattage output.
The 168 bulb draws 4.9W, while the 194 draws 3.78W. Although both fit a T10 wedge socket, substituting one for the other results in a difference in power consumption.
The 89 bulb is a single-filament type with a BA15s bayonet base, which is a mechanically different mounting style from the wedge base used by the 168 and 194. The three bulb types are not interchangeable with one another.
The 89 bulb operates at 12V and 13W, a notably higher wattage than either the 168 or 194, as it is a lower wattage variant of the 1156 bulb family.
All three bulb types conform to ANSI standards applicable in both the United States and Canada.
The Isuzu I-Mark (1987-1989) uses the 168 bulb for the license plate position across all three of those model years.
The 194 bulb is specified for the 1981-1982 and 1984 and 1986 model years, while the 89 bulb is specified for 1983 and 1985, indicating alternating fitment between those two types during the mid-production period.