The GMC V1500 Suburban uses a 168 bulb size for front side marker lights and a 194 bulb size for rear side marker applications. The replacement chart covers 1987 to 1991 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC V1500 Suburban uses two distinct bulb sizes across its side marker positions: the 168 at the front and the 194 at the rear, both applied consistently across the 1987-1991 model years.
Both the 168 and 194 are ANSI-standardized bulbs recognized in the United States and Canada, meaning they conform to a defined set of electrical and physical standards shared across those markets.
Both bulbs share the T10 miniature wedge form factor, a small, wedge-shaped base design that requires no locking mechanism and is retained by socket tension alone.
Both bulbs operate on a 12-volt electrical system, which is consistent with standard automotive low-voltage architecture.
The 168 bulb carries a rated wattage of 4.9W, while the 194 is rated at 3.78W, making the rear side marker the lower-power of the two positions on the GMC V1500 Suburban.
Although the 168 and 194 share the same T10 wedge base and voltage rating, their wattage values differ, and the two are not interchangeable without accounting for that difference in power draw.