Saturn Ion Dome Light Bulb Size

The Saturn Ion dome light requires a 561 bulb size for proper installation within the interior overhead lighting fixture. Data for the specified component covers the period from 2003 through 2007.

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
2003-2007	561

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 44mm length, end-cap contacts. 12V, 12W.	561

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Additional Notes

The Saturn Ion uses the 561 bulb size for the dome light across the 2003-2007 model years.
The 561 is an ANSI-standardized bulb type, meaning it conforms to a defined specification recognized in both the United States and Canada.
The 561 is a festoon-style bulb, which is a cylindrical lamp that makes electrical contact through metal caps at each end rather than through a base socket.
The 561 bulb operates at 12 volts and draws 12 watts, which is consistent with standard automotive low-voltage electrical systems.
The 561 bulb has a 44mm length, which is the critical fitment factor for festoon bulbs, as the housing span must match the bulb length for the end-cap contacts to seat correctly.
Because festoon bulbs rely on end-cap contact rather than a keyed base, substitution with another festoon bulb is physically possible only when the replacement shares the same 44mm length and compatible voltage and wattage ratings.