Ram ProMaster City Tail Light Bulb Size

The Ram ProMaster City tail light requires a P21/5W bulb size for proper illumination and function within the rear housing assembly. Available data for the specified component covers the period from 2015 through 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
2015-2022	P21/5W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W

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Additional Notes

The Ram ProMaster City uses the P21/5W bulb size across all listed model years, spanning 2015-2022.
The P21/5W is an ECE-standard bulb, a specification framework used in Europe and internationally, meaning it conforms to internationally recognized automotive lighting regulations rather than SAE standards common in North America.
As a dual-filament bulb, the P21/5W houses two separate filaments within a single glass envelope, with the 21W filament serving the brake or turn signal function and the 5W filament serving the tail or running light function.
The P21/5W operates at 12 volts, consistent with standard automotive electrical systems.
The bulb uses a BAY15d bayonet base, which is an offset twin-pin base. The offset pin placement is a deliberate design feature that prevents incorrect insertion, ensuring the two filaments are always oriented to their correct circuits.
The BAY15d base is not interchangeable with the BA15s single-filament bayonet base or the BAY15s offset single-pin base, as those configurations do not support dual-filament operation.