The GMC C2500 side marker utilizes a 194 bulb size for the lighting components located on the exterior of the vehicle. Data for the specified bulb covers the range from 1995 to 2000.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC C2500 uses two bulb types across its front and rear side marker positions: the 194 and the 168. Both are ANSI-standard miniature wedge bulbs sharing the T10 form factor and a 12-volt operating voltage.
The 194 bulb draws 3.78 watts, while the 168 draws 4.9 watts. Despite their identical T10 form factor, the wattage difference means the two types are not electrically equivalent and are not interchangeable without consideration of circuit load.
The 194 bulb is the more widely used of the two across the C2500 lineup, appearing in both front and rear side marker positions across the majority of model years covered in the specifications.
The GMC C2500 front side marker used the 168 bulb from 1979-1986, then transitioned to the 194 bulb starting with the 1988 model year, where it remained through 2000.
The 1990-1991 front side marker fitment of the 194 bulb carries a conditional note specifying applicability to vehicles equipped with Halogen Capsule Headlamps, indicating a trim or package dependency for those two model years.
The rear side marker position uses the 194 bulb exclusively across all listed model years, with no equivalent transition to the 168 bulb recorded for that position.
The T10 wedge base is a pinless design that seats by friction within the socket, which is a standard characteristic of miniature wedge bulbs in this category.
Both the 194 and 168 carry ANSI standardization recognized in both the United States and Canada, meaning bulbs sourced from either market conform to the same dimensional and electrical standards for their respective types.