Mack Granite (GU) Parking Light Bulb Size

The Mack Granite (GU) parking light bulb uses a 194NA size. The replacement chart covers vehicle production years from 2011 to 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	US Type	EU Type	Shop
2011-2022	194NA	WY5W	Check Price

Description	Type	Shop
ANSI standard (US & Canada). Miniature wedge bulb (T10), natural amber glass. 12V, 3.78W.	194NA	Check Price

The Mack Granite (GU) uses the 194NA bulb for its parking lights across the 2011-2022 model years.
The 194NA is an ANSI-standardized bulb, meaning it conforms to a defined set of electrical and physical specifications recognized across the United States and Canada.
The bulb follows the T10 wedge form factor, a miniature wedge-base design that connects without a separate socket pin, relying instead on the tension of the base itself to maintain contact.
The "NA" suffix in the 194NA designation indicates natural amber glass, which produces an amber-colored output through the tint of the glass envelope rather than through a colored lens or coating.
The 194NA operates at 12 volts and draws 3.78 watts, placing it in the low-wattage range typical of parking and marker light applications.
The standard 194 bulb shares the same T10 wedge base and 12V/3.78W electrical rating as the 194NA, but it has a clear glass envelope. The two are not interchangeable in applications where amber output is required by regulation, as the 194 would not produce the same colored light.