Mitsubishi Galant Back Up Light Bulb Size

The Mitsubishi Galant back up light utilizes 7440, 921, 1156, P21W, and 3497 bulb sizes depending on the specific production version of the vehicle. Available data for the lighting components spans from 1985 through 2012.

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
2010-2012	7440
2004-2009	921
1999-2003	1156
1997-1998	3497
1989-1996	1156
1985-1987	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	3497

Other Locations

Additional Notes

The Mitsubishi Galant back up light specifications span model years 1985 through 2012 and reference four distinct bulb sizes: 7440, 921, 1156, and 3497.
The 1156 is the most frequently specified bulb across the Galant lineup, covering model years 1985-1996 and 1999-2003, with the exception of 1997-1998. It is a single-filament bulb with a BA15s bayonet base rated at 12V and 21W.
The 3497 bulb, specified for the 1997-1998 Mitsubishi Galant, shares the same BA15s bayonet base, voltage, and wattage as the 1156 and is formally classified as a variant of it. Despite this similarity, the two carry separate ANSI designations and are not guaranteed to be interchangeable without verification.
Model years 2004-2009 use the 921 bulb, a T15 wedge-base type rated at 12V and 16W. Its wedge construction requires no locking mechanism, as the socket itself retains the bulb through friction.
The 921 operates at 16W, which is lower than the 21W rating shared by the 7440, 1156, and 3497 bulbs also found in this vehicle's history.
Model years 2010-2012 use the 7440 bulb, a T20 single-filament wedge type rated at 12V and 21W. The T20 wedge base is physically larger than the T15 wedge base used by the 921, making the two incompatible despite both being wedge-style bulbs.
The transition from the 921 to the 7440 between the 2009 and 2010 model years represents a shift to a higher-wattage bulb and a larger wedge base format, meaning parts from the 2004-2009 range are not directly transferable to 2010-2012 vehicles.
All four bulb types referenced in these specifications conform to ANSI standards applicable in both the United States and Canada, and all operate on a 12-volt system.
The 1156 and 3497 both use the BA15s bayonet base, which features a single contact pin offset to one side. This base type is distinct from the wedge bases used by the 921 and 7440, and the socket designs are not interchangeable between bayonet and wedge formats.