Ram 2500 Map Light Bulb Size

The Ram 2500 map light utilizes bulb sizes 212-2 and 578 according to the provided specifications for the interior lighting components. Available data covers the range from 2011 through 2023 without listing specific individual details for every single period.

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 Type	Shop
2023	212-2	Check Price
2013-2020	578	Check Price
2011-2012	212-2	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Festoon bulb, 41mm length, SV8.5 base. 12V, 12W.	212-2	Check Price
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V, 12W.	578	Check Price

Other Locations

Additional Notes

The Ram 2500 map light uses two bulb types across its model years: the 212-2 and the 578. Both are ANSI-standardized festoon bulbs rated at 12 volts and 12 watts, sharing a 41mm length.
The 578 bulb is specified for the Ram 2500 from 2013-2020, making it the more widely used of the two types across this application.
The 212-2 bulb is specified for the 2011-2012 and 2023 model years.
Although the 212-2 and 578 share identical voltage, wattage, and length, they differ in base design. The 212-2 uses an SV8.5 base, while the 578 uses end-cap contacts. These two types are not interchangeable despite their physical similarities.
The SV8.5 base on the 212-2 is a center-contact festoon fitting, where the bulb makes electrical contact through a single point at each end cap via a spring-loaded socket. The 578 relies on direct metal contact at both flat end caps without a protruding center pin.