GMC G3500 License Plate Bulb Size

The GMC G3500 license plate component utilizes 194 and 67 bulb sizes for illumination across various production versions. Available information covers the specific time range from 1979 through 1996.

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
1996	194
1979-1995	67

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 8W.	67

Other Locations

Additional Notes

The GMC G3500 license plate bulb specification changed once across the model years covered, with the bulb 67 used from 1979-1995 and the bulb 194 introduced for the 1996 model year.
The bulb 67 is an ANSI-standard single-filament bulb rated at 12V and 8W, fitted with a BA15s bayonet base. The BA15s base features a single contact pin, which physically distinguishes it from dual-contact bayonet bases and limits interchangeability to sockets of the same type.
The bulb 67 is a lower-wattage variant of the 1156 bulb. Both share the BA15s bayonet base, but their wattage ratings differ, which is a relevant factor when evaluating substitution between the two types.
The bulb 194 is an ANSI-standard miniature wedge bulb of the T10 form factor, rated at 12V and 3.78W. Its wedge base relies on direct contact pressure rather than a pin-and-socket locking mechanism.
The two bulb types used across the GMC G3500 license plate position, the 67 and the 194, are not interchangeable. Their base types are fundamentally different, with the 67 using a BA15s bayonet fitting and the 194 using a wedge base, making cross-year substitution physically incompatible.
The wattage difference between the two bulb types is notable. The bulb 67 draws 8W while the bulb 194 draws 3.78W, meaning the 1996 model year specification calls for a significantly lower power draw at the license plate position compared to earlier years.