GMC C3500 License Plate Bulb Size

The GMC C3500 license plate light uses 194 and 67 bulb sizes for the exterior illumination components. Available data covers the production span from 1979 through 2000 for the specified vehicle.

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
1988-2000	194
1979-1986	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 C3500 uses two distinct bulb types across its license plate light fitment history: the 194 and the 67, each with a different base type and wattage rating.
Model years 1988-2000 of the GMC C3500 take the 194 bulb for the license plate position.
The 194 is a T10 miniature wedge bulb rated at 12V and 3.78W, conforming to ANSI standards recognized in both the US and Canada.
The wedge base of the 194 is held in place by friction rather than a locking mechanism, which distinguishes it from bayonet-style bulbs used in other positions.
Model years 1979-1986 of the C3500 use the 67 bulb for the license plate position.
The 67 bulb uses a BA15s single-contact bayonet base, a base type that requires an alignment and twist motion to seat and release, unlike the wedge-style 194.
At 12V and 8W, the 67 draws more than twice the wattage of the 194, meaning the two bulbs are not interchangeable despite both being 12V single-filament types.
The 67 is a lower-wattage variant of the 1156 bulb family, sharing the same BA15s bayonet base but differing in wattage, so the 1156 is not a direct substitute for the 67 in this application.
Both the 194 and the 67 meet ANSI standards for the US and Canadian markets, indicating standardized performance and dimensional specifications within their respective bulb families.
Because the 194 and the 67 use physically incompatible base types, a socket designed for one will not accept the other, making base type a critical factor when sourcing a replacement for any given model year.