The Peterbilt 310 uses a 194 bulb size for front side marker applications and an 1816 bulb size for rear side marker applications. The replacement chart covers 1986 to 1987 production 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 Peterbilt 310 uses two distinct bulb types across its side marker positions for the 1986-1987 model years: the 194 at the front and the 1816 at the rear.
Both the 194 and 1816 are ANSI-standardized bulbs recognized in the United States and Canada, meaning they conform to a defined set of electrical and physical specifications.
The 194 is a T10 miniature wedge bulb operating at 12V with a power draw of 3.78W, making it one of the most widely used small indicator bulbs in automotive applications.
The 1816 is a T3.25 miniature wedge bulb, also rated at 12V but drawing 4W, placing it slightly above the 194 in power consumption.
Although both bulbs share the same wedge base design and 12V operating voltage, the T10 and T3.25 designations refer to different physical envelope sizes, which affects physical fitment in the socket.
The T3.25 designation of the 1816 indicates a tubular glass envelope roughly 3.25 eighths of an inch wide, while the T10 of the 194 corresponds to a 10 millimeter wide envelope, reflecting a difference in the two bulb sizing conventions used across ANSI standards.
Because the 194 and 1816 differ in both envelope size and wattage, they are not interchangeable between the front and rear side marker positions on the Peterbilt 310.