Lexus SC400 Dome Light Bulb Size

Additional Notes

• The Lexus SC400 uses the DE3175 bulb size for the dome light across all model years covered in the specifications, spanning 1992-2000.
• The DE3175 is a festoon-type bulb, meaning it is cylindrical in shape and makes electrical contact through metal caps at each end rather than through a base socket.
• Festoon bulbs are held in place by spring-loaded clips that press against the end caps, a mounting method common in interior dome and map light applications.
• The DE3175 designation follows ANSI standards recognized in both the United States and Canada, indicating a standardized specification for the bulb's physical and electrical properties.
• The "31mm" in the DE3175 designation refers to the length of the bulb, which is the critical fitment factor for festoon bulbs since the spring clips must apply tension across that specific span.
• The bulb operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
• Because festoon bulbs are defined by their length, substituting a bulb of a different length, such as a 28mm or 36mm festoon, would result in an improper fit within the SC400's dome light housing.
• The DE3175 shares physical compatibility with other festoon bulbs of the same 31mm length, such as the 3175 designation, which may be relevant when sourcing replacement bulbs across different product lines.