Ram 1500 Dome Light Bulb Size

The Ram 1500 dome light utilizes a 578 bulb size for interior illumination within the cabin area. Provided information covers a specific range of production from 2011 through 2024.

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
2023-2024	578
2011-2021	578

Bulb Specifications

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

Other Locations

Additional Notes

The Ram 1500 uses the 578 bulb for the dome light across the 2011-2024 model years, with no variation in bulb size across this entire span.
The 578 is a festoon-style bulb, meaning it is cylindrical in shape with metal end-cap contacts on each end rather than a base or pin configuration.
The 578 bulb has a length of 41mm, which is the critical fitment factor for festoon bulbs, as the housing spring clips must match the bulb's end-to-end length to maintain proper contact.
The 578 operates at 12 volts and 12 watts, which is consistent with standard automotive interior lighting powered directly from a vehicle's 12V electrical system.
The 578 carries ANSI standardization recognized in both the United States and Canada, meaning the specification is consistent across North American replacement bulb products.
Festoon bulbs of different lengths are not interchangeable even when voltage and wattage ratings match, so a 578 replacement must be confirmed at 41mm to seat correctly in the Ram 1500 dome light housing.