Acura RDX Stepwell Bulb Size

The Acura RDX stepwell light utilizes 158 and 194 bulb sizes for the interior lighting system. Data for the specific components covers the time range from 2013 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

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
2020-2024	158	158	Check Price
2013-2018	194	W5W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3W.	158	Check Price
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with W2.1x9.5d wedge base. 12V, 5W.	W5W	Check Price

Other Locations

Additional Notes

The Acura RDX stepwell position uses two distinct bulb sizes across its model years: the 158 for 2020-2024 and the 194 for 2013-2018.
Both the 158 and 194 are ANSI-standardized miniature wedge bulbs classified under the T10 envelope, operating on a 12-volt circuit.
The 158 bulb carries a rated wattage of 3W, while the 194 draws 3.78W, making the two types electrically non-equivalent despite sharing the same T10 physical form factor.
Because the 158 and 194 share the T10 wedge base, they are physically interchangeable in the socket, yet their differing wattage ratings means one is not a direct electrical substitute for the other.
The shared T10 wedge base is a two-pin configuration where the bulb is retained by the tension of the socket walls rather than a bayonet or screw mechanism.
The 2019 model year does not appear in the Acura RDX stepwell specifications, and no bulb size is associated with it in the provided data.