GMC Sierra Stepwell Bulb Size

The GMC Sierra stepwell bulb accommodates 2 distinct bulb sizes: 168 and 194, with each size corresponding to specific vehicle configurations. The replacement chart covers 1999 through 2006 production years and details the bulb size specifications for each model year.

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	US Type	EU Type	Shop
2001-2006	168	W5W	Check Price
1999-2000	168 (Door Light)	W5W	Check Price
1999-2000	194 (Stepwell Light)	W5W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with W2.1x9.5d wedge base. 12V, 5W.	W5W	Check Price
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194	Check Price

Other Locations

Additional Notes

The GMC Sierra uses the 168 bulb as its stepwell bulb size across the 2001-2006 model years, with no sub-position distinctions noted for those years.
The 1999 and 2000 Sierra models split the stepwell lighting into two separate positions, with the door light using a 168 bulb and the stepwell light using a 194 bulb.
Both the 168 and 194 are ANSI-standardized miniature wedge bulbs rated at 12 volts, sharing the same T10 wedge base form factor.
Despite sharing the same T10 base, the 168 and 194 bulbs are not identical in power draw. The 168 operates at 4.9 watts, while the 194 operates at 3.78 watts.
The wattage difference between the 168 and 194 means that substituting one for the other in the 1999 and 2000 Sierra may result in unintended brightness variation between the door light and stepwell light positions.
The ANSI designation for both bulbs confirms they conform to a shared North American standardization framework covering the United States and Canada.