Isuzu I-Mark Dome Light Bulb Size

The Isuzu I-Mark dome light requires a unique DE3175 bulb size for proper installation within the interior lighting housing. Available data for the specified bulb covers the range from 1985 to 1986.

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
1985-1986	DE3175

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 31mm length, end-cap contacts. 12V.	DE3175

Other Locations

Additional Notes

The DE3175 is the dome light bulb size for the Isuzu I-Mark across the 1985-1986 model years.
The DE3175 follows the ANSI standard, meaning it meets the electrical and dimensional specifications recognized across the United States and Canada.
As a festoon-type bulb, the DE3175 seats horizontally within a cylindrical holder, making contact at both ends rather than through a base socket.
The DE3175 has a physical length of 31mm, which is a defining factor in festoon bulb fitment, as holders are sized to match specific lengths.
End-cap contacts on the DE3175 mean the bulb conducts electricity through metal caps at each tip, a design common to festoon bulbs used in interior lighting applications.
The DE3175 operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles of that era.
Festoon bulbs of differing lengths are not interchangeable even when voltage ratings match, as an incorrect length will prevent proper contact within the holder.