Chevrolet Express Map Light Bulb Size

Chevrolet Express map light bulb size specifications include 578 and 561 bulb options across multiple production generations. The replacement chart covers vehicle data spanning from 1996 to 2022.

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
2003-2022	578
1996-2002	561

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V, 12W.	578
ANSI standard (US & Canada). Festoon bulb, 44mm length, end-cap contacts. 12V, 12W.	561

Other Locations

Additional Notes

The Chevrolet Express map light uses the 578 bulb for model years 2003-2022 and the 561 bulb for model years 1996-2002.
Both the 578 and 561 are festoon-type bulbs, meaning they are cylindrical in shape and make electrical contact through metal caps at each end rather than through a base socket.
Both bulbs operate at 12 volts and 12 watts, making them identical in electrical load despite their different size designations.
The 578 bulb has a 41mm length, while the 561 measures 44mm. This 3mm difference means the two types are not interchangeable, as festoon bulbs must span the contact points of their holder to function correctly.
Both bulb types conform to ANSI standards applicable in the United States and Canada.
The 578 is the sole map light bulb size across the 2003-2022 Chevrolet Express, representing a consistent fitment across two decades of production.
Because festoon bulbs rely on physical length to maintain contact with their holder, installing a bulb of the wrong length in the Chevrolet Express map light housing would result in either a loose fit or an inability to seat properly.