Fiat 124 Spider Dome Light Bulb Size

The Fiat 124 Spider dome light requires a 6411 bulb size for the interior lighting system. Data for the specified component covers the range from 2017 to 2020.

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
2017-2020	6411

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6411

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Additional Notes

The Fiat 124 Spider uses the 6411 bulb for its dome light across the 2017-2020 model years.
The 6411 is an ANSI-standardized bulb designation, meaning it conforms to a defined set of electrical and physical specifications recognized across the United States and Canada.
The 6411 is a festoon-style bulb, which means it is cylindrical in shape and mounts by pressing its two end caps into spring clips rather than inserting into a socket.
The bulb operates on 12 volts at 5 watts, which is consistent with standard low-draw interior lighting in passenger vehicles.
The 6411 uses an SV8.5 base, a designation that refers to the festoon cap width of 8.5mm, which must correspond to the spring clip spacing in the dome light housing.
The 36mm length of the 6411 is a critical fitment factor, as festoon bulbs are sized by their end-to-end length and a different length will not seat correctly in the housing clips.
Festoon bulbs of the same voltage and wattage but different lengths, such as 31mm or 41mm variants, are not interchangeable with the 6411 in this application despite their similar appearance.