Mazda 626 Back Up Light Bulb Size

The Mazda 626 back up light utilizes bulb sizes 921, P21W, and 1156 depending on the specific production version. Available information covers the range from 1979 through 2002.

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
1998-2002	921
1986-1997	1156
1979-1982	1156

Bulb Specifications

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

Other Locations

Additional Notes

The Mazda 626 back up light specifications cover model years 1979 through 2002, with two distinct bulb types used across that span.
The 1156 bulb is the more widely used of the two types, appearing across the 1979-1997 model years of the 626.
The 1156 is a single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base, which is a single-contact bayonet mount with a 15mm base width.
The BA15s bayonet base uses two offset pins to secure the bulb, a design that prevents rotation and ensures consistent filament alignment within the housing.
The 921 bulb is specified for the Mazda 626 across the 1998-2002 model years.
The 921 is a T15 wedge-base bulb rated at 12V and 16W, meaning it draws less wattage than the 1156 it replaced in later model years.
A T15 wedge base relies on the tension of the socket contacts against the glass envelope rather than a bayonet or screw mechanism to hold the bulb in place.
Both the 921 and 1156 conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances for those markets.
The 921 and 1156 use different base types, a wedge and a bayonet respectively, making them physically non-interchangeable despite both operating on a 12V system.
The wattage difference between the two bulbs, 16W for the 921 versus 21W for the 1156, means the socket and wiring specifications for each generation of the 626 are matched to their respective bulb type.